Nature of Sperm Whales’ Food.—“_Sepia Octopus_.”—Nautilus.
It has been before stated that the food of the sperm whale consists
almost wholly of an animal of the cuttle-fish kind, called by
whalemen “squid,” and by naturalists “_Sepia octopus_;” and at times,
when he is near the shore, he feeds upon small fish, which are
denominated “rock cod,” and which sometimes approach the size of a
moderate salmon.
But the instances in which fish of this description have been
ejected from the stomach of the sperm whale are but rare, while
every day’s experience proves that its common food consists of that
division of _molluscous_ animals which naturalists have denominated
“_Cephalopoda_,” and of which the “_Sepia octopus_,” or “sea squid,”
appears to be the most common.
A few words on the natural history of this highly organized and
remarkable animal can not fail to be interesting to the reader, as
it has excited the attention of naturalists for many ages, from the
remarkable nature of its formation and peculiar habits.
Endowed with all the five organs of sense, it is second to no
inhabitant of the mighty waters in the complete elaboration of its
organs, which has constantly rendered it a great object of attention
to the anatomist and physiologist.
Dr. Roget, in his _Bridgewater Treatise_, under the head of
“_Cephalopoda_,” states that “we now arrive at a highly interesting
family of mollusca, denominated _Cephalopoda_, and distinguished
above all the preceding orders by being endowed with a much more
elaborate organization and a far wider range of faculties. The
_Cephalopoda_ have been so named from the position of certain organs
of progressive motion which are situated on the head, and, like
the tentacula of the polypus, surround the opening of the mouth.
These feet, or arms, or tentacula, if we choose to call them so,
are long, slender, and flexible processes, exceedingly irritable
and contractile in every part, and provided with numerous muscles,
which are capable of moving or twisting them in all directions with
extraordinary quickness and precision. They are thus capable of being
employed as instruments not only of progressive motion, but also of
prehension. For this purpose they are, in many species, peculiarly
well adapted, because, being perfectly flexible as well as highly
muscular, they twine with ease round any object of any shape, and
grasp it with prodigious force. In addition to these properties,
they derive a remarkable power of adhesion to the surfaces of bodies
from their being furnished with numerous suckers all along their
inner sides. Each of these suckers is usually supported on a narrow
neck or pedicle, and strengthened at its circumference by a ring
of cartilage. Their internal mechanism is more artificial than the
simple construction already described; for when the surface of the
disk is fully expanded, it is formed of a great number of small,
slender pieces, resembling teeth, closely set together, and extending
from the inner margin of the cartilaginous rings in the form of
converging radii to within a short distance of the centre, where they
leave a certain aperture.
“In the flattened state of the sucker, this aperture is filled by
the projecting part of a softer substance, which forms an interior
portion, capable of being detached from the flat circle of the
teeth when the sucker is in action, and of leaving an intervening
cavity. It is evident that by this mechanism, which combines the
properties of an accurate valve with an extensive cavity for
producing rarefaction, or the tendency to vacuum, the power of
adhesion is considerably augmented. So great is the force with which
the tentacula of the cuttle-fish adhere to bodies by means of this
apparatus, that, while their muscular fibres continue contracted, it
is easier to tear away the substance of the limb than to release it
from its attachment. Even in the dead animal we have found that the
suckers retain considerable powers of adhesion to any smooth surface
to which they may be applied.
“The _octopus_, which was the animal denominated polypus by
Aristotle, has eight arms of equal length, and contains in its
interior two very small rudimentary shells, formed by the inner
surface of the mantle. This shell becomes much more distinct in the
loligo, where it is cartilaginous, and shaped like the blade of a
sword. The internal shell of the common _sepia_ is large and broad,
and composed wholly of the carbonate of lime; it is well known by
the name of cuttle-fish bone. Its structure is extremely curious,
and deserves particular attention, as establishing the universality
of the principle which regulates the formation of shells, whether
external or internal, and from which structures differing much in
their outward appearance may result. It is composed of an immense
number of thin calcareous plates, arranged parallel to one another,
and connected by thousands of minute hollow pillars of the same
calcareous material, passing perpendicularly between the adjacent
surfaces. This shell is not adherent to any internal part of the
animal which has produced it, but is inclosed in a capsule, and
appears like a foreign body impacted in the midst of organs with
which, at first sight, it appears to have no relation. It no doubt
is of use in giving mechanical support to the soft substance of the
body, and especially to the surrounding muscular flesh; and this
probably contributes to the high energy which the animal displays in
all its movements. It has been regarded as an internal skeleton, but
it certainly has no pretensions to such a designation; for, although
enveloped by the mantle, it is still formed by that organ, and the
material of which it is composed still carbonate of lime. On both
these accounts it must be considered as a true shell, and classed
among the productions of the integuments. It differs, indeed, from
bony structures, which are composed of a different kind of material,
and formed on principles of growth totally dissimilar. Besides
tentacula, the _sepia_ is also provided with a pair of fleshy fins,
extending along the two sides of the body. The _loligo_ has similar
organs of a smaller size, and situated only at the extremity of the
body which is opposite to the head. They have been regarded as the
rudiments of true fins, which are organs developed in fishes, and
which are supported by slender bones; but no structure of this kind
exists in the fins of the _Cephalopoda_. In swimming, the organs
principally employed by cuttle-fish for giving an effective impulse
to the water are the tentacula. These they employ as oars, striking
with them from behind forward, so that their effort is to propel the
hinder part of the body, which is thus made to advance foremost,
the head following in the rear. They also use these organs as feet
for moving along the bottom of the sea. In their progress under
these circumstances, the head is always turned downward and the body
upward, so that the animal may be considered as literally walking on
its head!
“The necessity of this position for the feet arises probably from
the close investment of the mantle over the body; for, although the
mantle leaves an aperture in the neck for the entrance of water to
the respiratory organs, yet in other respects it forms a sack, closed
in every part except where the head, neck, and accompanying tentacula
protrude.
“In the _calamary_, as well as the common _sepia_, two of the arms
are much longer than the rest, and terminate in a thick cylindrical
portion, covered with numerous suckers, which may not inaptly be
compared to a hand. These processes are employed by cuttle-fish
as anchors, for the purpose of fixing themselves firmly to rocks
during violent agitations of the sea; and accordingly we find that
it is only the extremities of these bony tentacula that are provided
with suckers, while the short ones have them also along their whole
length. The other genera of _cephalopodous mollusca_ are, like
the _sepia_, provided with tentacula attached to the head. They
comprehend animals differing exceedingly in size, some being very
large, but a great number very minute, and even microscopic.”
Other animals of this kind inhabit shells, one of which is the
nautilus, which, says Roget, “possesses a shell exceedingly thin
and almost pellucid; probably for the sake of lightness, for it is
intended to be used as a boat. For the purpose of enabling the animal
to avail itself of the impulses of the air while it is thus floating
on the water, Nature has furnished it with a thin membrane, which she
has attached to two of the tentacula, so that it can be spread out
like a sail to catch the light winds which waft the animal forward
on its course. While its diminutive bark is thus scudding over the
surface of the deep, the assiduous navigator does not neglect to
apply its tentacula as oars on either side, to direct as well as to
accelerate its motion. No sooner does the breeze freshen and the sea
become ruffled than it hastens to take down its sail, and, quickly
drawing its tentacula within its shell, renders itself specifically
heavier than the water, and sinks immediately into more tranquil
regions beneath the surface.”
Sir William Jardine, in speaking of the food of the sperm whale,[4]
ventures to suggest to those who may have frequent opportunities of
observing whether this whale may not also frequently resort to the
_medusæ_, and minute fish which in so remarkable a manner supply food
to some of the smaller, as well as the other genera of the gigantic
whales. That there is an abundant supply of this sustenance, both in
the Antarctic Ocean and the more smiling latitudes of the southern
seas, can easily be proved by a reference to _Lesson’s Statements_,
and also to the _Journal_ of Captain Colnett, who, when near the
southern point of America, observes: “During this forenoon we
passed several fields of spawn, which caused the water to bear the
appearance of barley covering the surface of a bank.”
Arbigny also remarks that “there are immense tracts off the coast
of Brazil filled with small creatures so numerous as to impart a
red color to the sea.” “Statements of this sort,” observes Sir
William, “could easily be multiplied; and hence we can not but
suppose that this kind of food, which is ascertained to afford such
rich nourishment to the other great _cetacea_, may very possibly be
appropriated by the sperm whale to the same purpose.”
This is an unaccountable error on the part of the compiler of the
_Naturalists’ Library_. The apparent banks above mentioned, and
which we have ourselves frequently seen in various parts of the
ocean, are certainly formed by myriads of _medusæ_ and other small
animals, which form the sustenance of the _Balæna mysticetus_, or
right whale’s food, which consists of animals of the shrimp kind, and
other minute creatures, which are closely congregated and swarm in
those animated “banks,” but of which the sperm whale never partakes;
as it is not “very possible,” but quite impossible that he could do
so, however inclined he might be, on account of the organization of
his feeding apparatus, which may be readily seen when its form is
referred to.
The _Sepia octopus_, or “sea squid,” sometimes reaches an enormous
size. In the _Philosophical Transactions for 1758_ (777), after
having given an interesting description of a specimen sent for
examination, the editor states that “it can, by spreading its arms
abroad like a net, so fetter and entangle the prey they inclose
when they are drawn together as to render it incapable of exerting
its strength; for, however feeble these branches or arms may be
singly, their power united becomes surprising; and we are assured
Nature is so kind to these animals that if, in a struggle, any of
their arms are broken off, after some time they will grow again.
It is evident,” he continues, “from what has been said, that the
sea polypus or _octopus_ must be terrible to the inhabitants of the
waters in proportion to its size, for the close embraces of its arms
and adhesion of its suckers must render the efforts of its prey
ineffectual either for resistance or escape, unless it be endowed
with an extraordinary degree of strength.”
A gigantic _Cephalopoda_ was discovered by Drs. Bank and Solander, in
Captain Cook’s first voyage, floating dead upon the sea, surrounded
by birds, who were feeding on its remains. From the parts of this
specimen which are still preserved in the Hunterian Collection, and
which have always excited the attention of naturalists, it must have
measured at least six feet from the end of the tail to the end of the
tentacles.
But this last we must imagine a mere pigmy when we consider the
enormous dimensions of the one spoken of by Doctor Swediaus,[5] whose
tentacula or limbs measured twenty-seven feet in length. But let the
doctor speak for himself: “One of the gentlemen,” says he, “who was
so kind as to communicate to me his observations on this subject
(ambergris), also, ten years ago, caught a sperm whale that had in
its mouth a tentaculum of the _Sepia octopodia_ nearly twenty-seven
feet long! This did not appear its whole length, for one end was
corroded by digestion, so that, in its natural state, it may have
been a great deal longer. When we consider the enormous bulk of the
tentacula here spoken of, we shall cease to wonder at the common
saying of the fishermen, that the cuttle-fish is the largest fish of
the ocean.”
In Todd’s _Cyclopedia of Anatomy_ (529), treating of _Cephalopoda_,
in an admirable paper by Mr. Owen, it states that “the natives of
the Polynesian Islands, who dive for shell-fish, have a well-founded
dread and abhorrence of these formidable _Cephalopods_, and one
can not but feel surprised that their fears should have, perhaps,
exaggerated their dimensions and destructive attributes.”
The same learned writer, after having beautifully described another
animal of this order, observes: “Let the reader picture to himself
the projecting margin of the horny hook developed into a long,
curved, sharp-pointed claw, and these weapons clustered at the
expanded terminations of the arms, and arranged in a double alternate
series along the whole internal surface, and he will have some idea
of the formidable nature of the carnivorous _onychotenthis_.”
This species of _Cephalopoda_ is thus armed with those kind of teeth
at the termination of the tentacles in order to secure the agile,
slippery, and mucous-clad fishes on which it preys; and there is an
instance recorded in the works of a celebrated author on _Excursions
in the Mediterranean_, by which we perceive that these terrible
creatures sometimes prey upon men. The author says: “In those shallow
waters are caught great quantities of fish, by forming curved lines
or palisades some way out to sea with palm branches, by which the
fish that come up with the high water are retained when it recedes.
The _horrid polypus_, which is, however, greedily eaten, abounds, and
some are of enormous size. They prove, at times, highly dangerous to
bathers.
“An instance of this occurred a few years since. A Sardinian captain,
bathing at Jerbah, felt one of his feet grasped by one of these
animals; on this, with his other foot he tried to disengage himself,
but this limb was immediately seized by another of the monster’s
arms; he then endeavored to free himself with his hands, but these
also were firmly grasped by the polypus, and the poor man was shortly
after found drowned, with all his limbs strongly bound together by
the arms and legs of the fish; and it is extraordinary, that where
this happened the water is scarcely four feet in depth.”
Other species of these surprising animals, as the _calamaries_,
or “flying squid,” as they are termed by seamen, have the power
of propelling themselves through the atmosphere. “There is good
reason for believing,” says Mr. Owen, “that some of the small,
slender-bodied subulate species of this genus are enabled to strike
the water with such force as to raise themselves above the surface,
and dart, like the flying-fish, for a short distance through the
air.” We have seen very frequently, both in the North and South
Pacifc, tens of thousands of these animals dart simultaneously
out of the water when pursued by albicore or dolphins, and propel
themselves, head first, in a horizontal direction, for eighty or a
hundred yards, assisting their progression probably by a rotary or
_screwing_ motion of their arms or tentacles, which they have the
power of thus moving with singular velocity. This species also, as
well as the large _onychotenthis_, we are led to believe, often
serves the sperm whale for food. We have seen, on several occasions,
very large limbs of the latter species of squid floating on the
surface of the ocean, appearing as if bitten off by some animal,
most probably by the sperm whale; for, when these remains have been
seen, we always looked out most anxiously for those animals, and have
seldom been disappointed in seeing them within a few hours afterward.
[4] Naturalists’ Library, vol. vi, p. 162.
[5] Philosophical Transactions, vol. lxxiii., p. 226.