THE SPUR AND CRURAL GLAND
In both platypus and echidna there occurs on the inner side of each
hind limb of the male a movable spur. This is found in the young female
also; but in the full-grown female it has disappeared, leaving a
depression to mark the spot where it had been. This condition suggests
that the spur and depression are of the nature of secondary sexual
characters, and have something to do with reproduction. Such was the
general belief for twenty years after the first discovery of the
platypus. Then it was reported from Australia that the spur of the male
was capable of causing serious wounds, followed by dangerous symptoms
due to a venom expressed through the spur. Thus began a lengthy
controversy which has not yet been settled to the satisfaction of all.
Shaw (1799) described the spur as a sixth digit, but pointed out that
it resembled a strong, sharp spur. Home (1801, p. 72) made the first
surmise as to its function, and described it in the following terms:--
“In the male, just at the setting on of the heel, there is a strong
crooked spur, half an inch long, with a sharp point, which has a
joint between it and the foot, and is capable of motion in two
directions. When the point of it is brought close to the leg, the
spur is almost completely concealed among the hair; when directed
outwards, it projects considerably, and is very conspicuous. It
is probably by means of these spurs, or hooks, that the female is
kept from withdrawing herself in the act of copulation, since they
are very conveniently placed for laying hold of her body on that
particular occasion. The female has no spur of this kind.”[4]
In March 1817 extracts from a letter from Sir John Jamison, dated at
Regentville, New South Wales, September 10, 1816, were read before the
Linnean Society of London and published in the _Transactions_ for 1818
(pp. 584-5). Jamison writes:--
“I cannot avoid relating to you an extraordinary peculiarity which I
have lately discovered in the _Ornithorhynchus paradoxus_. The male
of this wonderful animal is provided with spurs on the hind feet or
legs, like a cock. The spur is situated over a cyst of venomous fluid,
and has a tube or cannula up its centre, through which the animal can,
like a serpent, force the poison when it inflicts its wound. I wounded
one with small shot; and on my overseer’s taking it out of the water,
it stuck its spurs into the palm and back of his right hand with such
force, and retained them in with such strength, that they could not
be withdrawn until it was killed.[5] The hand instantly swelled to a
prodigious bulk; and the inflammation having rapidly extended to his
shoulder, he was in a few minutes threatened with locked-jaw, and
exhibited all the symptoms of a person bitten by a venomous snake. The
pain from the first was insupportable, and cold sweats and sickness
of the stomach took place so alarmingly, that I found it necessary,
besides the external application of oil and vinegar, to administer
large quantities of the volatile alkali with opium, which I really
think preserved his life. He was obliged to keep his bed for several
days, and did not recover the perfect use of his hand for nine weeks.
This unexpected and extraordinary occurrence induced me to examine
the spur of the animal; and on pressing it down on the leg the fluid
squirted through the tube: but for what purpose Nature has so armed
these animals is as yet unknown to me.”
Blainville, also in 1817, described the canal in the spur and the cyst
at the base; as the specimen he examined was a skin only, he did not
find the gland. In the _Edinburgh Philosophical Journal_ (vol. vi,
1822, p. 184) it is mentioned that Dr. Traill confirmed the existence
of a canal through the spur, so small that he could not pass a
horse-hair through it, though a human hair passed.
In the same year an extract of a letter from Mr. Patrick Hill, Surgeon
in the Royal Navy, dated Sydney, 3rd January, 1821, and addressed to
the Secretary of the Linnean Society of London, was read before the
Society and printed in the _Transactions_ for the year, pp. 622-4. Hill
writes:--
“You will be gratified to learn, that I have been completely
successful in establishing our friend Sir John Jamison’s account of
the spur of the _Ornithorhynchus paradoxus_. I subjoin an extract
from my notes:
“_Sunday_, Oct. 1, 1820--On the banks of Campbell’s River. In the
morning shot a male _Ornithorhynchus_. On examination, soon after
it was killed, I observed near the extremity of the convex side
of the spur, a minute spot, like the orifice of a tube; and on
endeavouring to pass a bristle from this spot, three successive drops
of a limpid clear fluid issued from it. I then examined the other
spur with the same result. On dissecting the foot of the animal, I
found at the inner side of the root of the spur, immediately over
the articulation, a small cyst, which I cut into; it did not at that
time contain any fluid; but from it I, with great ease, passed a
horse-hair through the spur.[6] This preparation I have sent to you,
together with the dried cyst.”
Farther on he quotes Cookoogong, chief of the Boorah-Boorah tribe,
as being “perfectly aware that a wound from the spur of the male is
followed by swelling and great pain; but although he has seen many
cases of it, he has never known it fatal.”
Knox (1823, p. 38) describes and gives the first published figure
of the gland, duct, cyst, and spur _in situ_ in a dissection of the
leg. He opposes Home’s views as to the copulatory function, and is of
opinion that the spur must be a weapon of offence. In the same year
Home records the presence of the gland, and describes how Clift passed
mercury through the duct--an experiment which Knox also performed. The
specimen examined by Knox has a certain historic interest, it having
been sent to the Royal Museum of the University of Edinburgh by the
then Governor of New South Wales, Sir Thomas Brisbane.
In an anonymous article in the _Annales des Sciences Naturelles_ (ii,
1824, pp. 75-6) from which I have previously quoted, the statement is
made that Jamison first announced the perforation of the spur, that Van
der Hoeven could not find it, but that Meckel confirmed its existence,
as well as that of the gland, in a letter to Brechet, the editor of the
_Annales_.
In 1826 Knox recorded the presence of a rudimentary spur in the female
echidna, and claimed that this discovery disposed of Home’s suggestion
of a copulatory function.
Isidore Geoffroy’s article on _Ornithorhynchus_ in the _Dictionnaire
Classique d’Histoire Naturelle_, published in 1827, refers to a
publication by Dr. Parmeter in Sydney:--“Cet auteur établit que les
mâles emploient leur ergots pour tenir les femelles immobiles dans
l’acte de la copulation, et il a publié sur ce sujet un petit Mémoire
imprimé dans la Gazette de Sidney.”
Dr. Parmeter was in practice on the Hawkesbury River, and must have had
opportunities of observing the platypus, which was then so plentiful
there. A weary search through the pages of the _Sydney Gazette_
brought to light only two occurrences of his name, apart from casual
attendances at the inquests which formed so prominent a feature of the
early days. One of these is at the foot of an advertisement deploring
the fact that his patients were not paying their bills, and threatening
drastic action unless they mended their ways; the second was the
advertisement of a forthcoming publication, _The History of Australia
by T. Parmeter, M.D._, with a list of a few advance subscribers--but
it would seem that the work was not published. In the _Gazette_
of December 4, 1823, there does, however, appear a letter, signed
“Observator,” which is almost certainly the memoir referred to.
Like most early statements about the platypus, it contains more
conjecture than observation. It is a comment on an excerpt concerning
Knox’s dissection of the spur and gland which had appeared in a
previous issue. Parmeter says:--
“I take leave to remark, that I have dissected this animal
particularly, to ascertain this much controverted point, and have
not been able to trace, either in the _living_ or _dead_ animal, the
virus supposed to be contained in the sac; and I am not _solitary_ in
my opinion, that _there is no poison_; nor is it, properly speaking,
a _gland_, which the spur is conjoined to.... That the plectrum
answers the particular purpose of a _prehensile_, is more rational
to conjecture, than that nature should have furnished the male with
a weapon (offensive or defensive), and not similarly provided the
female.”
This can scarcely be said to justify Isidore Geoffroy’s statement that
Parmeter has established the fact that the males employ their spurs to
hold the females. Further on in Parmeter’s letter the following lines
occur:--
“I therefore invite any Member of this infant Association[7] to
correct me, from an _authenticated fact, of any individual having
been injured from the wound of this animal’s spur_.”
This, from a medical practitioner who lived for many years among the
farming community on the banks of the Hawkesbury at a time when the
platypus was notoriously abundant in that river, and yet who had never
known of a case of injury from its spurs, points to the great rarity of
such an occurrence. The reason is that fully ninety per cent would be
drowned in the fish-nets, and the remainder killed before being handled.
In 1829 there appeared in the _Edinburgh New Philosophical Journal_
a letter from Thomas Axford, Esq., dated from Thorpe, Tasmania, 30th
June, 1828. He writes (p. 400):--
“It is my firm conviction that the animal has not the power of
instilling poison by its spur; and I believe this appendage is used
principally for securing the female in the season of love, though it
may also be useful in enabling the animal to climb the steep banks
of rivers. I have taken several large females, and I suppose old
ones, with the hair worn off, and only the fine fur left on their
rump; and although I have killed very large males, never found one in
that state.[8] The moment I saw the first old female thus denuded, it
struck me that the denudation must arise from the action of the spur
of the male in holding the female.”
Verreaux (1848, pp. 130, 133) stated that the spurs were used to hold
the female in copulation, being applied to her posterior part; and
that, though he had handled many male platypus, none had ever attempted
to use its spurs as weapons of offence against him. Dr. Bennett records
the same experience. He endeavoured (1860, p. 107) to incite the animal
to use its spurs, placing it in a variety of positions, and teasing it
to make it angry, but without success. He was convinced that the spur
was not used for offensive purposes. Krefft (1871) writes:--
“It is possible that the spur has some poisonous properties during
certain seasons of the year, because we remember being cautioned
to handle a male Water-mole, by a gentleman who said that he once
had been wounded in the arm by one, and had suffered severely in
consequence.”
Spicer (1876, pp. 162-3) records the case of Mr. Augustus Simson, of
Gould’s country in Tasmania, in a communication read before the Royal
Society of Tasmania on 13 November, 1876:--
“About three weeks ago, he and Mr. Stephens, the School Inspector,
were walking by the side of a lagoon, when their attention was
attracted by a Platypus, which had swum across from the other side,
and was on the point of making its way under the bank. Mr. Simson,
an active, energetic man, at once rushed down the bank, and secured
the animal. Now, I fancy, this fact alone is worthy of record; for of
all the shy wary animals in existence, Platypus is amongst the shiest
and most wary. Under ordinary circumstances, it is no easy matter to
catch even a passing sight of one; but here the creature was caught
in open daylight....’ The platypus was put safely in a bag, but
escaped. Mr. Stephens now takes up the story:--
“After an exciting chase, Platypus was recaptured;[9] but this time
he revenged himself by giving my friend a severe wound on the hand,
one spur slightly tearing the palm, and the other the back of the
hand, making a deep puncture between the knuckles of (I think) the
first and second fingers. The pain from this was intense, and almost
paralysing. But for the administration of small doses of brandy,
he would have fainted on the spot. As it was, it was half an hour
before he could stand without support. By that time the arm was
swollen to the shoulder, and quite useless, and the pain in the hand
very severe. No ammonia was to be had; no medical assistance was
available; and the only treatment that could be adopted, was to keep
the whole arm for a night and a day in wet bandages, which seemed to
alleviate the pain a little, and to reduce the inflammation.
“A week later I was informed by letter that the swelling had
subsided, the hand being still very tender, with a sensation as
of a severe bruise. From this time there was a slow but gradual
improvement.”
A letter from the victim substantiates this statement, and he adds (p.
163):--“Some natives tell me they would rather lay hold of a snake than
a Platypus.” On the same page Stephens describes the mode of attack,
which was precisely the same in this case as in that described by
Jamison:--
“The mode of attack is not by scratching, but by a powerful lateral
and inward movement of the hind legs, the spurs being thus brought
together like the points of a pair of callipers.”
The late Professor Sir Anderson Stuart, of the University of Sydney,
records further cases of poisoning in his Presidential Address to the
Royal Society of New South Wales, published in the Society’s _Journal_
for 1894. His account, which occurs on pp. 5-9, is as follows:--
“I have no doubt whatever that it is, at least at certain seasons,
a powerful poison. I have from time to time made enquiry, and have
also advertised for information, and I have two good accounts from
very intelligent hunters of the animal, in widely separated parts of
the Colony, which coincide perfectly, so that I have no doubt myself
that they accurately represent the main features of the action of the
poison in dogs and as observable by laymen.
“One account shows that the males fight very fiercely while in the
water during the pairing season, mostly applying themselves to each
other belly to belly. The scratches are mostly on the under surface
of the tail. The females are very seldom found scratched. One of the
hunters tells of a dog he had which was ‘stung’ on three different
occasions--each time both spurs were employed, and the wounds were
always on the dog’s cheeks. The wounds are always described as on
the head or face somewhere, because they are inflicted while the dog
is retrieving the wounded animal. The effects followed very quickly,
like the sting of a bee. Within a couple of minutes the head began
to swell, and on the first occasion had reached a ‘tremendous’ size
within a quarter of an hour. This swelling gradually disappeared, and
was gone in thirty-six, ten, and three hours on the first, second,
and third occasions respectively. The swelling and all the other
symptoms were less marked the second than they were the first time,
and the third than the second time. The swollen head was tender to
touch, for the dog ‘sang out’ when it was touched there. The eyes
were at first closed up by the swelling, and when again visible were
‘wild-looking.’ The dog became sleepy, as if under the influence of
a strong narcotic, so that he had to be carried to the camp, and he
moaned from time to time. The dog would neither eat nor drink, but
there was no salivation, vomiting, diarrhoea, tremor, convulsions,
nor staggering. Breathing was difficult, but not very. This dog quite
recovered.
“My other account is from one of two brothers who were both great
hunters of platypus, and he confesses to having been wicked enough
to have shot many thousands during his thirty-two years of work.
He had four valuable water-dogs that died from the ‘stings.’ On
one occasion he actually saw the platypus strike, heard the dog
whine, saw the wound, and the train of symptoms ending in death.
These were comparatively large dogs. He knew that after he himself
gave up hunting, his brother, who went on with it, lost dogs too.
The drowsiness was so intense that he has had to carry the dogs on
horseback with him for as long as three hours.”
Here follow details of the accounts given by Jamison and Spicer, which
are quoted above. Anderson Stuart sums up (p. 9):--
“Now if we review these four accounts, we note that--
“1. They are all absolutely independent, not one writer knowing
anything of the other three, three hailing from different parts of
the colony of New South Wales, and one from Tasmania, and all from
different periods of time.
“2. Two were in the human subject and the rest in dogs.
“3. The train of symptoms, _mutatis mutandis_, agree most perfectly.
“4. In all cases the poison was allowed to follow its natural course,
nothing but external applications, if anything at all, being ever
employed by way of treatment.
“5. The symptoms were specific, and differed entirely from the
ordinary surgical effects of lacerated wounds.”
He concludes that the gland secretes a powerful poison at certain
seasons, probably during pairing-time.
Martin and Tidswell (1894) made a chemical examination of the fluid
secreted by the crural gland, and an inquiry into its physiological
effect when injected into rabbits. Their paper gives an excellent
summary of the history of the controversy, and mentions cases of
poisoning other than those given above. Thus on p. 476:--
“Under the heading: ‘The Poison of the Platypus’, the following
extract from the _Maitland Mercury_ is quoted in the _Australian
Journal of Education_ (1869):--‘On Tuesday, the 9th instant, when
Mr. E. was fishing in the river near his residence, he found that a
Platypus had got entangled in the net, and upon catching the animal
it immediately struck the two spurs attached to its floats or arms
into the forefinger of Mr. E.’s left hand, with such force that they
penetrated through the skin and into the muscles of the finger,
and it was with great difficulty that Mr. E. at last succeeded in
ridding himself of his unwelcome intruder and eventually killed
it. Mr. E. all the time suffered intense pain, and presently the
wounded finger, then the hand, and ultimately the whole arm up to the
shoulder swelled to a serious extent. The symptoms usually following
snake-bite also set in, and after a day or two Mr. E’s state became
so serious as to alarm his friends for his safety, and Dr. G. having
been sent for, he applied ammonia and the usual remedies against
snake poison, and we are glad to learn that Mr. E. has now entirely
recovered.’”
On p. 479 Martin and Tidswell quote A. Nicols (_Zoological Notes_,
London, 1882, p. 116):--
“A. Nicols records having wounded and captured a Platypus which
was lively enough to scratch him with its sharp claws, but made no
attempt to use its spurs when handled. The native who accompanied
him, however, expressed fear of the spur. Nicols thought that
the spur and its gland might be ‘a remnant of conditions of life
very different from those under which the animal now exists.’ He
considered that, although it might possibly be used in contests
with its own kind, ‘there is no reason for attributing a poisonous
character to this weapon.’”
On p. 480 the authors mention four more cases (two in men and two
in dogs) recorded by Dr. Lalor in a communication abstracted in the
_British Medical Journal_ for June, 1894, p. 1332. There is thus a
considerable body of evidence for the poisonous nature of the secretion.
Martin and Tidswell proceed (pp. 482-487) to an examination of the
anatomy and histology of the gland and duct, which they figure on their
Plate XXVIII. The glands are more or less kidney-shaped bodies, with
the concave border outwards, symmetrically disposed on either side of
the vertebral column above the acetabulum and femur. Each gland lies
in a special compartment of the deep fascia, covered by the panniculus
carnosus and skin, between the muscles of the leg on the outer side,
and the gluteus maximus on the inner. An average gland measures 3 cm.
in length, 2 cm. in breadth at its widest part, and about 1.5 cm. in
thickness. The surface is lobulated.
The duct emerges from the posterior half of the outer border, and
passes downwards, with the nerves and blood-vessels, on the posterior
aspect of the leg. It measures about 5 cm. in length, and, in an
undilated state, about 2 mm. in external diameter. After leaving the
gland it passes down under the biceps muscle, crosses the tendon of
the gastrocnemius, and reaches the spur. Here it becomes dilated into
a sac, which is so deeply embedded in the ligamentous tissue at the
back of the tarsus that its isolation is a matter of difficulty. From
this dilation a prolongation extends into the canal in the spur, which
is attached to a supernumerary tarsal ossicle, articulated to the
astragalus and tibia.
The gland is enclosed in a capsule consisting of an outer layer of
unstriped muscle, three or four cells deep, and an inner coat of white
fibrous tissue, which is continued into the mass of the gland as a
stroma separating the alveoli. It is of the compound racemose type.
The duct, traced into the gland, divides repeatedly into smaller and
smaller branches; the final branches open into the alveoli, which are
dilated, and lined by a single layer of epithelial cells situated upon
a basement membrane.
Sections across the duct show that it possesses a single lumen close
to the spur, which becomes multiple as it is traced backwards towards
the gland. The wall is composed of fibrous tissue, without any muscular
elements whatever, and is lined by an epithelium composed of four
layers of cells. The saccular dilatation at the base of the spur has
the same structure.
The fluid secretion, which is described as ‘limpid and opalescent’ by
Martin and Tidswell, was chemically examined, with the following result
(p. 490):--
“Our conclusions as to the composition of the secretion drawn from
the above experiments are:--
(1) It is a solution of proteids.
(2) That the greater portion is composed of a proteid belonging to
the class of albumins, and that in addition a small quantity of
proteose is present.
(3) Nucleo-albumins are absent.”
The authors remark that the toxicity of snake venom is known to be due
to its proteose content; but in their experiments with the platypus
fluid, because of the smallness of the quantity of material available,
it was not possible for them to separate the proteose from the albumin.
Consequently the limited number of experiments which were possible had
to be made with the mixture.
_Experiment I_: A rabbit had .05 gramme of the ‘poison,’ dissolved in
5 cc. of .75-salt solution, injected under the skin of the abdomen.
Upon the following day a swelling the size of a duck’s egg had appeared
near the seat of the injection, which was tender to the touch. The
animal was sick, with dull eye, eating sparingly, and its temperature
had risen by one degree Fahrenheit. A day later, the swelling and
temperature were reduced, the animal was much livelier and taking food.
In a couple of days more it had completely recovered.
_Experiment II_: 6 cc. of a solution of the dried poison in .75-salt
solution, of such strength that the dose actually contained .06 gramme
of the actual gland secretion, was injected through a cannula into the
jugular vein of an etherized rabbit. The experiment was arranged so
that a simultaneous record of blood-pressure, respiratory movement,
and time-rate was recorded upon a revolving drum covered with smoked
paper. Within three seconds from the commencement of the injection the
blood-pressure fell by 40 mm. of mercury, the heart-beats becoming
less frequent. At the same time the respiration became hurried and
exaggerated, and speedily terminated in a series of expiratory
convulsions, in the course of which the blood-pressure rose again, but
speedily fell. In a minute and a half the animal was dead. An immediate
post-mortem disclosed that the right side of the heart and the whole
of the venous system were full of clotted blood; the left chambers of
the heart and the pulmonary veins contained fluid blood, and there was
an extensive endocardial haemorrhage. Martin notes that this condition
is precisely similar to that induced in rabbits by the intra-venous
injection of snake venoms.
Two further experiments were made similar to the latter of the two
above, but with smaller doses of poison. The dose for _Experiment III_
on p. 494 of the paper is given as 0.4 gramme, but this obviously
should read 0.04 gramme. The former quantity was equal to the total
amount of poison held by the investigators (see p. 496). _Experiment
III_ gave the same ultimate result as _Experiment II_, but at a slower
rate; in _Experiment IV_ the blood was not clotted, but on being drawn
off coagulated at a rate much slower than the normal.
The authors claim that these experiments prove the secretion of the
gland to contain some body capable of producing very considerable toxic
action when introduced into the bodies of rabbits. They admit that this
toxic agent may be of other than proteid nature, but do not think it
likely, since the results resemble those produced by proteid poisons.
The whole of the experiments, including the apparently contradictory
result obtained in _Experiment IV_, show a close agreement with results
obtained by use of snake venoms. The venom of snake is, however, 5000
times as virulent as the preparation of platypus poison used. The
latter appears to be much more powerful in the production of local
oedema.
Their final conclusions follow (pp. 498-9):--
“At the conclusion of our survey of the literature of this subject,
we pronounced the opinion that as far as the evidence adduced went,
it presented a very strong case in favour of the contention that
these glands, at any rate at some seasons, produce a poisonous
secretion.
“We venture to think that the results of our experiments have
established the fact that the secretion is poisonous at some time of
the year. Whether the animal is capable of discharging a secretion
possessed of poisonous properties at all seasons of the year is not
at present determined. Creighton states definitely that the gland is
subject to seasonal variations in size just as is the case with the
mammary gland and testes (Bennett). We have been unable to find on
what evidence Creighton makes this statement; but the differences in
minute structure observed by us lend support to this view.[10]
“The idea naturally occurs to one that this apparatus, which is
confined to the male sex, owes its peculiar development to the
operation of sexual selection. That it is a weapon used by the males
on one another when conflicting for the possession of the females,
is an idea which would become extremely probable if it could be
established that the gland is specially developed at or about the
pairing season. This is a point which could be settled without
difficulty, provided specimens could be obtained in sufficient number
at suitable periods of the year, say August and February.
“Bennett found developing ova in the uterus as early as September, so
that in all probability the animals pair during the latter part of
August and earlier part of September.
“That the secretion obtained by us from the glands of an animal
killed in June proved actively poisonous, whilst that from an animal
killed in April was innocuous, is interesting in this respect,
although June would indicate a somewhat early preparation for
pairing. We cannot, however, place much stress on this isolated
observation, as it is quite possible that the difference in
development was due to quite other causes. In the meantime the
biological significance of these extraordinary organs must remain an
open question.”
The following interesting measurements and dates were recorded by me
after dissecting three robust adult male platypus during the rut of
1923.
Testes Crural
Macdonald River, N. England, 8-10-’23 7 × 10 mm. 9 × 20 mm.
Namoi River, Manilla, 10-10-’23 22 × 30 mm. 15 × 44 mm.
Namoi River, Manilla, 23-10-’23 5 × 10 mm. 8 × 20 mm.
The last two males were taken in the same locality.
Although I omitted to measure the scent-glands, I observed that their
size was in proportion to that of the testes and crural glands.
This, then, suggests to me sexual affinity, so to speak, between all
three sets of glands in or out of season, and furthermore, that such
conditions prevail until all are gradually exhausted. This may occur
late or early during the rut, according to circumstances.
An aboriginal once informed me that he had seen the male platypus
carrying nesting-material by means of its spurs. I do not, however, put
much trust in this story, for, so far as I have observed, the female
builds the nest unaided. As regards bachelor quarters (even during
the cold months), all the males that I have unearthed to date were in
cavities of bare earth.
We have, then, a mass of evidence, contradictory in nature, yet adduced
by competent observers. It will be of interest to summarize the
suggestions which have been put forward as to the function of the spur,
and to see whether the apparent contradictions cannot be reconciled.
The suggestions made are five in number:
(1). That put forward by several early naturalists (e.g. Axford), that
it aided the animal in climbing banks. This may be dismissed without
further comment, for it is quite obvious that the female has greater
need of bank-climbing apparatus--if such be necessary at all--than the
male.
(2). The suggestion by Baden-Powell, quoted by Spicer, that the
secretion is simply a dressing for the fur, a function which, it will
be remembered, Geoffroy Saint-Hilaire once suggested for the mammary
gland. Here, again, if an oil for the fur be needed, the need of the
female is as great as that of the male. Moreover, although the hair is
combed principally by means of the claws of the hind foot, the spur is
not suitably placed for assisting in the operation.
(3). The suggestion of Nicols, quoted by Martin and Tidswell, that the
spurs are a remnant of conditions of life very different from those
under which the animal now exists. Martin and Tidswell remark (p. 480)
that, while it is very difficult to show that the suggestion is false,
it does not appear to be reasonable. A complicated arrangement, in a
condition of functional perfection, would hardly be retained if it were
of no service to the individual or the species. With this I agree.
(4). The position taken by Jamison, Knox, Spicer, Martin and Tidswell,
and others, that the spur and gland are weapons for the infliction of
poisonous wounds, either upon other males when fighting for possession
of the female, or upon enemies in general. The evidence for seasonal
variation in the functional activity of the gland is definite enough,
but is insufficient to rule out the notion that the spur is a weapon
of offence against enemies in general. The demand for protection from
enemies is not seasonal; it is an affair of all the year round, and the
spur is dangerous at all times.
As one of the uses of the spur is almost certainly to inflict poisonous
wounds, it is probably directed against other males of its own species
as well as against natural enemies. One other observer besides myself
(Verreaux) has claimed to have seen the act of mating. Here at least I
have confirmatory evidence that this act takes place in the water. As
to whether Verreaux’s description of the event is in every particular
correct or otherwise, I am not concerned. There is, of course, no
doubt that the secretion, when introduced into the blood-stream of a
mammal, has a powerful toxic effect, and Martin and Tidswell claim no
more than this. When two males fight, I judge from the position which
they take up at first that the introduction of the venom is designed by
both combatants. Combats among mammals for possession of the female are
rarely fought to the death. They are, admittedly, at times severe, but
are tests of physical strength and endurance, in which the weaker goes
to the wall with nothing more than a few wounds. I have known platypus
males placed together in confinement disagree with, and sometimes kill,
one another, though I have no evidence that death was caused by poison
from the spurs. But I have always thought that such might be the case.
Before solving the problem of keeping platypus in captivity for
exhibition purposes, I handled many freshly-trapped uninjured males,
first while collecting, and later with specimens imprisoned in a
contraption which I termed, at that time, a “Platypusary.” Realizing
that the less handling the animals received, the better for the test, I
did not ruffle their tempers more than was necessary. Not once during
manœuvrings did a male make any attempt to use his spurs on me. I
naturally came to the hasty conclusion (as others have done) that male
platypus are ridiculously docile, good-tempered creatures.
Since then my opinion of them in this respect has changed, and for
this reason. I placed two freshly-caught adult males together (in the
breeding-season) in a large tub half-filled with water. After several
endeavours to crawl up the sides of the tub--which I prevented them
from doing--they became enraged, not only with me, but, apparently,
with themselves and one another. Presently a quarrel began in earnest;
they were floating side by side at the time, each with its head to its
opponent’s tail. As they became more and more tightly pressed together
for their full length, they circled around as one centrally-pivoted
concern. This was caused by each combatant, with gaping jaws,
strenuously endeavouring to catch hold of the other’s tail at the tip.
Each in turn eventually succeeded and hung on tenaciously as though all
depended on this remarkable grip. Both seemed so concerned that now my
presence appeared to be unheeded. Wriggling and paddling began with
vim, presumably with the object of one turning the other over without
being overturned itself. Had this fight been waged in deep water, it is
difficult to imagine what advantage either would obtain over the other.
Ultimately there was a great splash, and the antagonists were in firm
holds, heads to tails, for their full length, beneath the water; but on
bumping the foreign bottom they instantly released their holds and came
to the surface for a blow. As I could not induce them to battle again,
I released them into the Namoi River.
It is worth noting here that, while under water in the locked position
as described, the vital external jugular veins of each (mentioned
by Martin and Tidswell) would be exposed, and nothing less than a
timely parry with the versatile fore-paws would suffice to prevent a
death-dealing puncture, if not actually in the jugular vein, then in
close proximity to it. In any case, if this did occur it could hardly
be called accidental. As in the case of all fauna in a fight to a
finish the combatants would probably receive many wounds in different
parts before one was totally disabled.
This, then, brings me to another point. If the “dope” (as I term
it) is not of a deadly nature during the mating session, why is
it always ejected by the animal when it deliberately spurs at an
enemy? Hoy’s encounter with an infuriated male in the height of the
breeding-season[11] convinces me that the secretion is used for
offensive rather than for amatory purposes.
Before placing the males together in the tub I experimented with
the larger of the two (weighing exactly four pounds) purposely to
explode my initial theory that males will not intentionally use their
spurs when being handled. Of course, I knew the truth even then, but
I required sufficient proof to satisfy the most sceptical. This is
what occurred: I first placed a special rubber gauntlet over my right
forearm, then gloved that hand adequately, leaving my left free for
minor purposes. After placing the robust male platypus on a table,
abdomen uppermost and tail towards me, with my bare hand I held the
wriggling creature by the head. Then, to exasperate him, I placed my
right arm on his tail and deliberately tantalized him by tickling him
from back legs to brisket with my fingers. Several times he raised his
spurs simultaneously as if sparring for a grip, but each time lowered
them again. Tiring of such monotonous behaviour, I removed my arm to
rearrange his position and to reverse my hand-holds temporarily. But,
while I was bringing my bare hand back to grasp his tail, the platypus,
as though aware that I was off my guard, like a flash struck with his
spur and ripped the edge of my left hand for a distance of over an inch
towards the little finger. This action was so quick and unexpected that
it certainly gave me a shock. After placing the platypus back in the
box, I repeatedly squeezed the wound and made it bleed very freely.
My wife then took a hand, and flooded the wound with iodine twice
within half an hour; each time she did so, the pain was acute in the
extreme--far more so than when first inflicted. The rip, which was
jagged by my tearing away from the temporarily rigid spur, was 1⅛
inch in length, and ⅛ inch in depth. Now, whether the pulling away of
my hand simultaneously with the striking of the spur saved me from
receiving a full dose of dope, or any at all, is questionable. But two
or three days later, when I had almost forgotten the event, I felt a
slight pain under the arm, and noticed a redness leading thereto from
the wound. Nothing more serious developed; but it occurred to me that,
as the iodine entered the wound, so the secretion administered with the
prod of a spur, during conflict, although not a deadly poison, might at
any rate cause sufficient pain, when injected into a wound, to cause
the rival at once to desist. If so, nothing more is necessary when
duelling for possession of the gentler sex.
While on this subject, I will explain why and how the platypus is
capable of inflicting very severe wounds with its spurs. When the
animal is not anxious or prepared to grip, the spur may be lifted
back with one’s thumb and forefinger. This, I know, has led most
observers to suggest that the power of the grip would be insufficient
to penetrate the pelt of an adult platypus. If the spur were rigid like
that of a cock, and used in a like manner, all would readily agree
to such a possibility. Well, I can assure my readers that when the
platypus feels inclined, and is prepared to strike, the position of
the spur can be styled as rigid. That is to say, it is propped back to
the extreme point of erection, where, when striking, it will tear all
before it, or become dislocated in the attempt. But the driving power
then brought to bear is not alone in controlling the precise movements
of the spur. All the leg muscles concerned in the sudden twisting of an
ankle combine to force the weapon home. I am speaking from personal
experience with wild specimens in the field--not from pickled carcasses.
[Illustration: (1) POISON GLAND CONNECTED BY DUCT TO WELL AT BASE OF
SPUR. DISSECTED SPURS AND THEIR INNER TUBES.
(_From fresh carcass_)
_Plate 14_]
From experiment and observations made in connection with the actual
voluntary administration of poison by an enraged platypus, and also by
personally lifting to full-cock the clamped weapon of another fresh
carcass, I came to the conclusion that, in the erection of the spur
to a given point, say, from half-cock to full, the poison dose is
regulated accordingly. For instance, when the spur is fully cocked the
fluid will flow until a dew-like drop appears at the orifice near the
tip. Here, ready for immediate action, the weapon stands fully charged.
Its mission at this stage is first to puncture, with solid tip, the
skin of the opposing subject. By so doing, the tip readily tears a way,
thus preventing clogging of the orifice until the poison makes contact
with at least first blood. The desire of the animal is to strike at
a vulnerable spot, and the flow of poison would probably be stemmed
temporarily if the spur were embedded deeply; but whether the amount of
poison is measured automatically at the cocking of the spur, or whether
the platypus is able to control the flow after striking, has not been
determined. But the fact must be noted that, when the animal attempts
to insert the spur and misjudges the mark, the spur is carried on into
the fur of its own leg, and the dose spilt thereon is apparently in
greater quantity than that which the tube of the spur could possibly
hold with the one filling. Seemingly, then, the well at the base of the
heel is drained also with the complete clamping of the spur, having
been shut off from the main supply at the initial filling. It seems
reasonable to suppose that the spur must be re-cocked before a similar
operation can take place, otherwise there would probably be a constant
leakage while the spur is clamped normally out of action.
[Illustration: (2) GENERAL VIEW OF MALE PLATYPUS, UNEARTHED FROM
CAMPING BURROW.
_Plate 14_]
Apart from the controversy as to whether the poison is deadly or not,
I strongly advise the uninitiated not to meddle recklessly with a male
platypus, in or out of season, for I am quite convinced that when once
the animal grips correctly, especially with both spurs, unless the
platypus releases voluntarily (which he is not likely to do readily)
the creature would surely have to be killed before the spurs could be
extracted. Failing this, there is obviously only one other way out of
it, and that is to lance or tear the tortured flesh of the victim.
The sudden twist of the ankles, referred to above, may best be
illustrated thus. Clench both fists, place the hands side by side with
the fingers uppermost, then open the palms to the extreme, suddenly,
and note the rigid position of thumbs. While in that position, regard
the palms as the soles of platypus feet, and the extended thumbs as
“set-back” spurs. Of course, in the case of the platypus the incurved
shape would incline towards the finger-tips, but to follow this curve
with the thumbs the rigidity essential for striking purposes would
be lost. Very well, let that be understood. At this point, then,
imagine an enemy to be lodged in the palms, and held there firmly by
clutching talons. This may be represented by clamping the extremities
of the fingers tightly, without closing the palms. Then, with a jerk
simultaneously twist both wrists inwards to the full, finishing with
the backs of the hands uppermost, and thumbs clenched beneath. This
will serve to convey some idea as to the awkward position of the victim
so secured by an infuriated platypus.
Of an endeavour to test the effect of platypus poison on a
freshly-trapped rabbit my report is as follows. Not being fully
equipped with the poison collected directly from the spurs of a living
specimen, because of its being swabbed up by the fur on the thigh of
the animal each time the fluid was ejected through the then clamped
spur, I was compelled to extract the secretion from the glands of a
freshly-killed specimen. Using a hypodermic syringe, I injected into
the thigh muscle (not a vital part) of the rabbit what I considered
to be a double dose of the poison, that is to say, as much as the
platypus would inject with both spurs simultaneously. I observed the
rabbit closely for two hours after, but did not notice any change in
its behaviour. My final examination, twenty-four hours later, found
the subject very quiet, but otherwise apparently well. On killing
the rabbit I found a discoloured swelling of the muscle surrounding
the punctured portion, and between the skin and muscle a frothy
cream-coloured corruption, quite foreign to the immediate conditions of
those parts. This then is slight evidence that, at least, the rabbit
suffered pain, but to what extent I could not estimate. Still, if the
effect is sudden, as I believe, then it would serve the essential
purpose of putting an opponent temporarily out of action at the desired
moment, and for a sufficient length of time.
Where the method of striking has been observed and described, observers
agree that the hind legs are brought together, causing a wound on both
sides of the intervening object, which must be of comparatively small
dimensions--a finger, a hand on edge, or the sharp muzzle of a dog. The
animals concerned are wounded in several instances and badly frightened
in others.
Taking warning from the mistakes of zoologists who have, in the past,
argued plausibly about the platypus, only to be proved wrong in the
end, one should refrain from argument unless armed with practical
experience and observation in the field. My observations of the method
of copulation were made without thought as to the function of the
spurs, and I think they prove clearly that that function is definitely
connected with copulation. This brings us to the fifth suggestion:--
(5). That the spurs are used for holding the female during the sexual
embrace. This suggestion was first put forward by Home in 1802. He
elaborated it in his _Lectures on Comparative Anatomy_ (1823), in which
he writes:--
“When I first saw the spur, I had no doubt from its situation but
that one of its purposes was to prevent the escape of the female
during the act of the coitus; in this I was confirmed when I found in
the female, exactly in the same situation, a regular socket, lined
with strong cuticle, adapted to the reception of the spur.... Having
ascertained that a secretion is emitted through the spur of the male
into this socket, and the parts being so minute as to require glasses
of considerable power, I got Mr. Bauer to examine the socket in the
female; and after overcoming considerable difficulties, the parts
being very much corrugated, and yet retaining their elasticity, he
made out the form of this socket, which corresponds exactly in shape
to the spur itself: so that, when completely introduced, it must be
so grasped that the male would be unable to withdraw it when coitus
was over; in this respect resembling the effect of suction. The
male, it would appear--at least this is the best conjecture I can
make by reasoning from analogy, there being no facts to guide us--by
throwing some of the secretion of the gland in the thigh into the
socket, dilates it, and releases the spur; the liquor injected being
acrimonious, will also irritate the female, and make her use efforts
to escape.”[12]
Martin and Tidswell (_loc. cit._, p. 481) comment on the above as
follows:--
“Home’s suggestion, which had the powerful support of Dr. Bennett,
cannot be absolutely denied, as no one has, as far as we are aware,
ever seen these animals copulating. Home’s main reason for such an
hypothesis was that in the female there are situated in corresponding
situations slight hairless depressions.
“It seems to us that for the male to apply its spurs to these
depressions during copulation in the manner suggested by Home
would involve an amount of gymnastic ability of which even an
_Ornithorhynchus_ is incapable.
“Moreover, Knox and Owen have shown that these depressions in the
female are merely the rudiments of the male spur, and that the young
female, indeed, actually possesses a spur which disappears prior to
the dawn of sexual life.”
The statement contained in the last paragraph seems capable of an
interpretation very different from that of Martin and Tidswell. The
young of both sexes have a genital protuberance of similar size; in
the male it develops into the intromittent organ and in the female it
is found in a reduced condition as the comparatively insignificant
clitoris, situated on the margin of an invagination. The history of the
spur affords an exact analogy.
Until of late years I was under the impression that female platypus
might shed their spurs on attaining maturity, if not before leaving
the nest. On that account I was persistently on the look-out for
cast-offs among the nesting-material, where furred young were found.
Now, however, I have come to the conclusion that the spurs are retained
by the females, but that, instead of hardening like those of the male,
they soften and collapse within themselves to form the so-called socket
or calloused area about the ankles, which corresponds in dimensions
with the base of the male spur. This, then, would prevent the spur tip
from pricking, accidentally, the ankle of the female.
[Illustration: (1) SOLE OF RIGHT HIND FOOT, SHOWING SPUR NORMALLY
SHEATHED.
_Plate 15_]
[Illustration: (2) SOLE OF LEFT HIND FOOT, SHOWING SPUR IN ACTION.
Note trail of freshly-ejected venom on background.
_Plate 15_]
In my description of the method of copulation I think it is shown
conclusively that the platypus has the gymnastic ability to grip the
female with its spurs. Moreover, in the tail-to-tail position, which I
shall describe later as occurring throughout the greater part of the
coitus, the only possible grip the animals can have of one another is
by means of the spur and foot. That this use is feasible has been shown
by an experiment with recently killed animals, used while they were
still in a pliable condition.
If we now turn to echidna, as we very well may--for an explanation
which is adequate for the platypus must be adequate also for the
echidna--what do we find? A gland is present, popliteal rather than
femoral in position (which leads Owen to prefer the word “crural”
as covering both), but much reduced in size, which is equal to that
of a small pea, with a reduced duct running to the spur. I rely on
Owen’s account in the _Penny Cyclopaedia_, confirmed by a recent
reinvestigation by Mackenzie and Owen (1919, p. 38), in which the
authors conclude:--“In our opinion this body shows evidence of
retrogression similar to that seen in the vermiform appendage and other
structures.”
No case of venomous wound caused by the spur has been recorded against
the echidna. Semon (1894, p. 7) writes as follows:--
“There can be no doubt that the spur of the male, and the glandular
apparatus connected with it, is to be looked upon as an organ for
sexual excitation. Without at present bringing forward any theory as
to the function of the organ, I can at least completely substantiate
Bennett’s observation that the significance of the spur is not as a
poison weapon, nor, indeed, any kind of weapon at all. Not one of
the hundreds of echidnas which I have handled in a living state ever
tried to use its spur as a weapon.”
It is generally believed that the echidna has evolved its spiny
covering for protective purposes, but it is obvious that spines are
useless as offensive weapons. Semon has apparently been influenced by
Home’s theory as to the use of the spur for sexual excitation, and by
Bennett’s opinion that the spur is not used as a poison weapon. His own
experience in handling hundreds of echidnas is not conclusive evidence
against the use of the spur as a weapon, for the reason that, when
handled, they tuck their legs within the protective covering of their
spines. The only way to prevent the echidna from rolling itself into a
ball is to place it on its back on a board, with straps at the corners
securing all its legs. In that position its spurs are out of action.
The animal apparently has no need of an offensive weapon against
enemies in general; but in all forms of animal life there is rivalry
among the males, and whether the echidna ever used, or still uses, its
spurs during copulation, or not, it would appear reasonable that the
spur is the natural weapon for males to use on each other, especially
as the only way in which they can possibly come together in combat is
on their hind legs, using the out-turned claws as supports, and with
the front of their bodies in contact for their full length. In this
position their spurs could be used on the only vulnerable portion of
each other, whereas, if the contest for possession of the female were
to be carried on in any other position, the result must be a stalemate
owing to the impregnable covering of spines.
Bill Lancaster, of Manilla, N.S.W. (who has been my assistant in field
work), informed me that only once in his sixty years of bush experience
did he see the echidna in the act of copulating. It occurred on the
side of a mountain. He described the participators as forming one
large ball of quills with a pair of muzzles just protruding at one end,
the whole resembling a spiny melon with split stalk attached. After a
minute or two Lancaster rolled them over with his boot and, as this had
no effect, he deliberately kicked them down the mountain side, but even
this failed to separate them and they remained together for some time
after reaching the flat ground below.
I have since examined many echidna specimens (both sexes) and noted
particularly the “cowlick” formation of their quills about the hinder
parts. These they are obviously unable to close down completely
even when walking in freedom in the bush, quite unaware of the
presence of an observer. I therefore consider it impossible for these
creatures to copulate in any other position than that described by
Lancaster--abdomen to abdomen, and head to head. Of course, they may
prefer to lie on their sides in the initial stages, but I consider
it more feasible for them to stand up on their hind legs, partly
supporting each other with their fore-paws until the desired position
is attained; after that, any attitude may be assumed; but, for the
sake of safety to both during the breakaway, the side-to-side movement
should prove the simplest.
On August 11, 1919, I examined the spurs of an adult male echidna, and
found them embedded in a swollen fleshy sheath on the external portion
of its heels, or lower legs. On pressing the sheath down, the spurs
appeared to shoot up suddenly, like a splinter from festered flesh.
Here I discovered, around the base of both spurs, a creamy-coloured
discharge, which I consider, if applied to an open wound, would not
tend to heal the flesh. The condition appeared to be quite normal, but
I do not know of any previous record of a similar observation, and
cannot offer any opinion as to its purpose, or whether it was peculiar
to the mating season.
If it is impossible for the male to make use of his spurs during
copulation while in the position described by Lancaster, the grip is
evidently obtained by the curiously-shaped long claws of both sexes.
Wood Jones (1923, p. 37) sums up the position in regard to the platypus
in the following terms:--
“Thoroughly reliable observations, however, carry us this far. The
male _Ornithorhynchus_ can, and at times does, strike with its spurs
when handled. The spurs are capable of inflicting a wound, and this
wound is followed by definite symptoms. The symptoms are somewhat
akin to those present in cases of non-fatal snake-bite, and men and
dogs are equally affected when wounded by the spur. So far as I can
ascertain, no recorded observations have ever given support to any of
the various opinions that the apparatus has functions other than that
of an offensive and defensive weapon. That the recorded observations
show that the spur is not invariably made use of when the animal is
handled, is of little moment.
“We may say, therefore, that the male Monotreme possesses a secreting
gland, a duct, and a hollow spur, as an anatomical entity; that the
gland undergoes seasonal changes in activity; that its secretion,
when injected into animals, is decidedly poisonous, and that its
composition, and its effects, are probably akin to those of snake
venom; that the symptoms produced by the experimental injection
of the secretion into animals are similar to those described in
well-authenticated cases of wounding of men, or dogs, by the spur of
the living male Platypus.
“Because we have limited ourselves to the statement of certain
well-ascertained facts concerning its use as a weapon, it must not
be imagined that it is considered impossible that the animal may
put the spur to other uses. The Monotremes are not easy animals to
observe, and possibly many of their habits remain quite unknown for
lack of proper opportunities for observation. But there is little to
be gained by mere speculation as to the function of structures found
in living animals. Observation of the living creature is required.”
Despite this judicial warning, I must plead guilty to indulgence in
speculation. It has, however, been based on observations which were
not available to Wood Jones. One concerns the method of copulation;
this observation is admittedly incomplete, and it will probably be
necessary to take a pair in the act of copulation to settle the matter.
The second may now be detailed.
While drying a male platypus upon my knee with a towel, I felt an
increasing pressure of the soles of the animal’s feet upon my thigh,
and hurriedly raised it, thinking that it might be trying to use
its spurs. I then noticed that the spurs had penetrated through a
fold in the cloth of my trousers, which was moist from the expressed
secretion. On experimenting further with this animal, I noted that
there was no attempt to strike with the spurs, as does a cock. The
intervening object was first grasped with the hind feet, which were
then pressed firmly against it, and the spurs were brought together
with a deliberate probing motion, which may be likened to the process
of sewing with a packing-needle.
Finally, there is the question of expression of the secretion. Several
observers have commented that they were unable to force it out by
pressure upon the gland and duct. Martin and Tidswell remark upon the
absence of muscular elements in the duct, and wonder how the secretion
is kept from wasting. The solution of the matter may be found in
Jamison’s observation--“This unexpected and extraordinary occurrence
induced me to examine the spur of the animal; and _on pressing it down
on the leg_ the fluid squirted through the tube” (1818, pp. 584-5). The
animal is, of course, able to bring this about by muscular action, and
is not dependent upon pressure against external objects for expression
of secretion. Plate 15 shows a photograph of the foot and spur of the
male referred to above. In preparation for taking the photograph, a
piece of card, in which a slit shaped like a button-hole had been
cut, was passed over the foot to serve as a background. In adjusting
this card so that the slit should not appear in the photograph, it
was revolved about a quarter turn, a process which caused continuous
irritation to the muscles above the base of the spur while the point
was resting on the card. The result was a trail of secretion which is
clearly visible in the illustration.
After weighing all the evidence, and as the result of my own
observations, I have therefore come to the conclusion that the uses
of the spur of the male platypus are those set out in the fourth and
fifth suggestions, namely, as weapons and for holding the female during
copulation.
[Illustration: UNEARTHING PLATYPUS, RETREAT STATION, MACDONALD RIVER,
N.S.W.
Note excavated burrow commencing at water-level, between figure of
collector and oak-tree at right, then winding up the bank to black
patch (near tussock grass) where nest was found.
_Plate 16_]