there are chiefly three species which are always remarkable for their
numbers or their characteristic form or appearance, and are scarcely
ever absent from one of the larger stretches of water. These are the
spur-winged goose, _Plectropterus gambensis_, the Egyptian goose,
_Chenalopex aegyptiacus_, and the pelican, _Pelecanus onocrotalus_. More
remarkable for their peculiar habits are the scissor-billed tern,
_Rhynchops flavirostris_, and the strange African darter, _Plotus
Lavaillantii_. The former is remarkable for the way and manner in which
it ploughs the water with its beak as it flies for the sake of catching
food, the latter for the strangeness of its movements—whether on the
water or on dry land—such as is displayed by none of its relatives or in
general by any other bird.
The central and south European migratory birds are certainly all to be
found in Bornu, in so far as they seek these latitudes in the winter-
time. One of the commonest sights during the dry weather is the ordinary
stork, _Ciconia alba_, which one may meet with in whole flocks along the
banks of Lake Chad, yet they do not as a rule mingle with the indigenous
long-legged birds. High in the air is seen the swift, _Micropus apus_,
and in the ‘bush’ one meets with many birds, which are well known to us
in Europe. The most commonly seen of these are the wryneck, _Jynx
torquilla_, the wheatear, _Saxicola oenanthe_, the wagtails, white,
Ray’s and blue-headed, the crested lark, _Alauda cristata_,[305] the
golden oriole, _Oriolus galbula_, and hoopoe, _Upupa epops_.
The reptiles and Ranidae of Bornu are at present only properly known in
those varieties which are often seen, or which are remarkable for the
benefit or damage which they cause.
Of the turtles, for whom, if only in parts, all the conditions of life
are forthcoming, the only one known at present is the _Sternothaerus
Adansoni_[306] living in the bed of the River Yedseram. On the other
hand, crocodiles, belonging to the species _Crocodilus vulgaris_, are to
be seen everywhere that collections of water worthy of the name are to
be found,[307] but they also stay, in places right up to the foot of the
mountains, in the smaller streams and pools, provided that a
communication, if only temporary, exists with the larger water-courses;
and it is surprising how they are able to maintain themselves here
during the dry weather. But of all places the crocodile is commonest in
Chad and in its affluents which contain continuously running water,
especially the Shari, where indeed one may see giant specimens—as much
as four metres long—sunning themselves with gaping jaws during the
hottest time of the day on the high sand-banks. The great quantity of
fish in the rivers prevents the mail-clad monsters as a rule from
attacking men and cattle, but the contrary does sometimes take
place—especially in the small but deep and dull-coloured water-courses.
In the reed-beds along the banks of the rivers and lakes often lurks the
giant water-monitor, _Varanus niloticus_, with its variegated markings,
while it is just the driest parts of the ‘bush’ that are the favourite
haunts of the thick-set dull earth-coloured land-monitor, _Varanus
exanthematicus_, which has few markings. Most of the smaller lizards are
quite domesticated. On every building, wall and roof, the beautiful blue
and red lizard, _Agama colonorum_, sports in the hottest sunshine, in
some places in company with a brown and white striped lizard with a
lively turquoise-blue tail. At night-time these lizards are relieved by
the confiding Geckoes, _Platydactylus_, who search the interior of the
houses for every kind of vermin and thus are of great utility.
In the millet fields and amongst the ‘bush’ trees are found several
varieties and large numbers of brightly-coloured chameleons, which
appear on the dry stubble after the conclusion of the harvest, and are
able, though not to so extensive a degree as is often supposed, to suit
their colouring to that of their surroundings.[308]
Quite large in many places is the number of snakes, among whom several
are very poisonous and of considerable size. By far the largest of all
is the python, _Python Sebae_, usually to be found in the neighbourhood
of the water-courses, but it is also fond of coming into the villages,
whose hen-roosts it plunders, but is otherwise harmless. It reaches a
considerable length; thus Barth secured a specimen, apparently belonging
to this species, that measured over five and a half metres.[309]
Distributed all over Bornu, but most commonly among the dunes undermined
by field-mice and hares on the south-western shore of Chad, where it
finds plenty of prey, is the puff-adder, _Vipera arietans_;[310] in
consideration of its size—it reaches a length of over a yard and is as
thick as a man’s arm—and its predilection for human habitations swarming
with rats, it is a dangerous and poisonous brute, but fortunately
evinces great laziness in the daytime. Commoner still is the ‘Efa’,
_Echis arenicola_, which in the cool nights seeks the warm houses of the
natives; its proper lurking-place is among the thick-knotted roots of
the fig-tree. To it appear attributable the majority of fatal accidents
from snake-bite.[311] The African cobra, _Naja haje_, the liveliest and
most truculent of the poisonous snakes, is found indeed everywhere, but
fortunately is distinctly rare. Finally, there is a very long green
tree-snake, which is credited by the natives with poisonous
qualities.[312]
Of Ranidae also there is no lack. All stagnant and sluggish flowing
water harbours crowds of semi-gigantic frogs. A bluish-grey variety with
a pointed head possesses the ability of making as much row as a flock of
crows, and after the rainy season has set in nightly drives to
desperation those travellers who are unable to accustom themselves to
the nocturnal noises of the tropics. Small silvery-grey tree-frogs with
a red belly—they belong to a widely-distributed species—are often found
in Southern Bornu clinging to the leaves.
The connecting link between the Ranidae and the fish tribe is a peculiar
animal found also in the Nile, the scaled salamander of Lake Chad,
_Lepidosiren annectens_, which, moreover, is a living argument in favour
of a former hydrographical connexion between the Chad countries and the
Nile. The Shuwa Arabs say the salamander is a savoury dish and are keen
on trapping it; the pear-shaped gelatinous capsules—generally hidden
among the matted roots of a papyrus bush—in which the animal spends the
dry season, are easily found in the dried-up soil on the banks of Lake
Chad.
Zoologically speaking the vertebrates that have been least sufficiently
investigated hitherto are the fish that live in Bornu waters. The little
that is known about them again shows a similarity with the fauna of the
Nile countries.[313] A thorough investigation here would contribute to
the solution of many geographical questions. Lake Chad and its affluents
are beyond all conception rich in fish, sometimes as big as a man in
size;[314] the fish ascend the streams far up to their very source, and
remain there even during the dry weather, provided that the water
outlasts it. Among the most savoury are several species of cat-fish,
which are extraordinarily abundant; at the fall of the water they make
shift to do with a very small quantity of moisture, and are able to last
out the temporary dryness in the humid mud. The best-known varieties are
the electric cat-fish, _Malapterurus electricus_,[315] the ‘Fahak’, or
‘puffer’, _Tetrodon fahaka_,[316] and a species of pike, _Polypterus
bicher_.[317] All three are also found in the Nile.
Whilst amongst the vertebrates of Bornu many represent species proper to
East Africa, the same is the case to an enhanced degree among the
invertebrates. Many classes of insects have almost without exception
East African shapes, and only quite a few West African. Certain kinds of
insects are even, considered purely from the point of view of animal
geography, the most interesting kinds of fauna that Bornu has to show.
The fact that numerous palearctic insects are also represented here is
partly to be explained by their considerable powers of flight; but it is
further noteworthy that the Sudan species, which have to undergo without
exception only a short larval stage, show with a quicker period of
generation a far smaller size than the corresponding European, i.e.
Mediterranean species.
In a country where the distinction between the wet and dry seasons is so
sharply defined as in Bornu, it is natural that the life of the legged
creatures, whose whole existence is closely bound up with the constant
moisture of the soil and atmosphere, is subject to considerable
fluctuations as regards abundance. Thus soon after the beginning of the
first rains great numbers of insects of all sorts appear, which indeed
decrease somewhat in the middle of the rainy season, to reach their
height during harvest time, whilst the winter is poor in insect-life.
Where the species appear in successive generations following each other
alike in the dry and in the rainy seasons—this holds good especially of
the butterflies—they are subject in a remarkable degree to the laws of
seasonal dimorphism, that is to say that the parts which remain visible
in repose, show a noteworthy adaptability to the colouring of their
surroundings. To the insects and such-like creatures, which are in
evidence at all times of the year, belong especially those whose
presence at any time is considered a nuisance, such as termites, ants,
or vermin.
Of all the insect genera the beetles are the best represented, not only
as regards number of species but also as regards splendour of
appearance.[318] Big camboid-beetles equipped with formidable
mandibles—to this species belong the giant _Anthia venator_, found all
over North Africa—gauzy-winged tiger-beetles, _Cicindelae_, which scurry
over the sand-banks, and big black water-beetles, _Cybister_, which
people all the ponds and pools, are the most rapacious among them. In
Bornu the chafer family is also rich both in appearance and species.
Everywhere on dung one meets big and little sleek black or metallic
tinted dung-beetles, whose giant variety is the elephant dung-beetle,
_Heliocopris Sandersi_, which builds long tunnels on the ground and is
the most powerful of dung-rollers. Whilst the _Dynastidae_ are very
scarce in the Sudan, the rose-beetles, or _Cetonidae_, are as prominent
in Bornu as everywhere else in Africa, both as regards number of
species, size, and colouring. Great quantities of these beetles, new and
surprising examples of which appear every month, are first seen
immediately after the beginning of the rains, when every flowering
acacia swarms with them. Very many species, and quite the most beautiful
ones, such as the white ant-eating _Gnathocera_ species with its zebra-
like markings of black, white, and yellow, or the big golden-green fork-
nosed _Eudicellae_ of South Bornu, seek the sap which flows from the
grasses and trees; at the slightest concussion of these drinking-places
they fly off with a loud buzzing.
Distinguished likewise by numerous species and brilliant colouring is
the family of gala-beetles, _Buprestidae_, and the long-horned beetles,
or _Cerambycidae_. Of the former there is a large and thoroughly
tropical variety, with golden-yellow marking on a ground like brown
leather, which is found even as far as the country of Aïr in the Sahara;
it is called _Sternocera castanea_.[319] Quantities of this giant beetle
swarm about the end of the rains on the big acacia trees, on whose
leaves they feed. On the dunes overgrown with broom on the banks of Chad
one finds the beautiful steel-blue _Caillaudi_ thickly powdered with
yellow, which belong to the _Buprestidae_ species, _Julodis_,
characteristic of the southern Mediterranean lands. The long-horned
beetles, usually with very variegated wing teguments, are remarkable for
the damage they do to timber. One large and active species of an orange-
yellow colour, striped with velvety black, the _Diastocera fasciata_, is
noteworthy for the way in which both males and females are wont to gnaw
off, like a beaver, quite large branches of certain trees, in order to
find a place to lay their eggs; the stumps thus sawn through are so
neatly done that they might have been produced by a turner’s lathe.[320]
Of the beetles that appear in large numbers, one should especially
mention the black _Pimeliae_, a true palearctic variety, which are to be
found in the sandy districts of Bornu, especially in the neighbourhood
of villages amongst dirt and rubbish. Finally, the fire-flies, whose
light may be observed at the beginning of the rains all the evening
everywhere in tree and bush, belong to the widely-distributed species of
_Lampyris_.
Besides the beetles the _Hymenopterae_ in Bornu also belong to the class
of insects who are of importance for the good service or the damage that
they do; thus the honey-bees are certainly as numerous as the varieties
belonging to this family which are hurtful to man. Wherever there are
fair-sized trees with hollows in them, and especially in South Bornu,
one may count with certainty on the presence of swarms of wild bees,
which are distinguished in no way from those of other parts of Africa,
as far as concerns viciousness and truculence, as all travellers have
reason to relate.[321] Nevertheless, the natives understand very well
how to get at the honey, and have also hit upon contrivances for
settling the bees in places decided on by themselves. Barth and
Nachtigal mention besides the tree-living bees a species which nests in
holes in the ground and produces a special kind of honey.[322] Whilst
the _Apis_ variety, to which the stinging honey-bee belongs, only
attacks one if one approaches its nest, its relative the non-stinging
_Melipona_ variety makes itself a regular pest by following man and
beast in whole swarms in order to suck their sweat, so that many
travellers, especially in view of the smaller size of the _Melipona_,
have been led to regard them as flies. Especially unpleasant is the
acrid smell which these _Hymenopterae_ diffuse when one kills them, and
this attracts still larger swarms of the intrusive insects.
The _Formicinae_, or ants, appear in Bornu in remarkable numbers though
not in such masses as in the primaeval forest region. Many are
apparently identified, even by travellers like Barth, with the termites,
and are thus held to some extent responsible for the latter’s
destructive activity,[323] yet they are ubiquitous and their
intrusiveness, though not always injurious, makes them in the highest
degree troublesome. It is only by making a barrier of oil or water that
one can protect oneself from their attentions. The driver-ant, too,
_Annoma_, that unpleasant visitor from the primaeval forest, appears,
according to Barth’s description, to be always present in the Central
Sudan.[324] At all events the ant fauna of Bornu is very large, and
Gerhard Rohlfs says with perfect truth: ‘No country could have so many
ants and such different species of them as Bornu.’[325] Nachtigal, too,
lays special stress on the number of species of ants.[326] Among the
most important species of _Hymenopterae_ living in Bornu is the sand-
wasp, _Pompilus_, remarkable for its size as well as for its brilliant
colouring.
Bornu is poor in butterflies, if one takes into comparison the
prodigious richness of the primaeval forest in such insects, at least as
far as one considers number of species. In spite of this it is just the
lepidopterous fauna of the country which is extraordinarily interesting.
Only one single variety is West African, all the others, so far as they
are not South European or cosmopolitan, or else of a general Ethiopian
character, are East African.
As far as butterflies are concerned, the shimmering _Nymphalidae_
species, in which the primaeval forest region is so rich, is almost
entirely unrepresented. Of important forest butterflies there are only
forthcoming some of the quick-flying _Charaxes_ species, which are
always hovering over the granite rocks of Southern Bornu, where they
feed on the sap oozing from the trees or on excrement. The _Precis_
species, corresponding to the European _Vanessa_ species, show
themselves during sharply defined periods of the year. Everywhere in the
‘bush’, especially feeding on elephant dung, is to be found the
cosmopolitan ‘painted lady’, _Pyrameis cardui_. The best represented of
all the butterflies are the whites, _Pieridae_, and amongst them again
the most numerous are the charming _Teracolus_ species, characteristic
of the Sudan, which with their variegated markings, their carmine or
bright blue beauty-spots flutter round the flowering _Capparis_
bushes—they come out especially also in the dry weather—and so form the
most beautiful living ornaments of the often desolate ‘bush’.[327] It is
also remarkable how exquisitively suited to this family is the golden-
red colouring of the under-side of the withered grasses during the dry
weather. The _Papilionidae_ species, which includes the largest sized
butterflies, is extremely scantily represented in Bornu; so remarkable
is this lack, that one of the species that is found, viz. the big black
and white _Papilio Schultzei_, is not only a very interesting insect
from the point of view of animal geography, but at the same time is also
the most interesting representative of the fauna of Bornu in general, so
far as it is known. This butterfly is only found in a few small places
among the granite rocks north of Uba, i.e. close to the border of
Adamawa. The nearest relatives of this butterfly are not found again
till east of Lake Victoria Nyanza in East Africa, that is, at a distance
of roughly 3,000 kilometres—the intervening countries, including the
highlands of Mandara, are apparently altogether without them; they were
considered as characteristic of East Africa until the discovery of this
new species. It is only geologists that may perhaps be in a position to
clear up this curiosity in Natural History, for this butterfly belongs
to those, who—like the European _Parnassiae_—are very unwilling to leave
their usual haunts and show not the slightest migratory propensity.
The moths, which especially among the _Noctuae_ exhibit many
Mediterranean varieties, are somewhat more richly represented than the
butterflies. The caterpillars of two variegated _Saturniidae_ of the
species _Epiphora_, which live on the _Zizyphus_ trees, belong to the
silk-cocoon producing family. These cocoons, however, are not employed
by the natives. Many kinds of caterpillars, which crowd the trees and
bushes soon after the first tornadoes, are eaten by the pagan tribes, as
is usual in Africa; amongst such caterpillars are those of the
_Saturniidae_, _Gonimbrasia osiris_,[328] which appear in regular
swarms.
An important and sometimes fatal rôle is played by the two-winged flies,
or _Dipterae_, for to them belong almost without exception in Bornu
those varieties of insects, who have been ascertained to be the chief
carriers of the disease germs, from which both man and beast have to
suffer. Even when this does not hold good, they are for the most part
perfect pests, which may become dangerous from their very numbers. All
travellers are aware of the quantities of mosquitoes, often to be
described as ‘in size equalling a large fly’,[329] which appear
especially along the rivers and on Lake Chad in regular clouds, and make
it impossible in many places for men and animals to stay there. Of these
blood-suckers, to which belong many species of the _Culex_ and
_Anopheles_ family—the female of the latter is the carrier of malaria—as
well as the diminutive sand-fly, _Simulia_, with a very irritating bite.
Denham says: ‘A chief told me near Kussery that during the last two
years he had lost two children, who were literally stung to death, and
from our own observation and sufferings this does not appear to be an
exaggeration.’[330]
There are also many other flies which are justly dreaded, such as the
numerous varieties of horse-flies and the dangerous _Glossinae_, the
female of which carries the tsetse-sickness among cattle and the
sleeping sickness among men,[331] though the latter has not yet been
observed in Bornu;[332] fortunately the tsetse-fly is only found in
certain tracts, but there it always causes more or less destruction
among cattle.[333] Barth as well as Nachtigal mentions the incredible
number of fleas in the houses of the natives;[334] on the other hand the
‘jigger’, _pulex penetrans_, which was introduced into Africa from
America at the beginning of the nineteenth century, has not yet
penetrated to Bornu.
The _Neuropterae_ are represented by the big _Myrmeleon_ species with
brown-spotted wings; they are three times as large as the European ant-
lion. The _Orthopterae_, as far as regards dragon-flies, are inferior to
the big metallic-glistening species of the primaeval forest, but the
southern districts especially excel in the family of the white ants.
Everywhere, especially in the acacia forest,[335] one meets with the
considerable erections, three or more metres in height, made by these
termites. The white ants bear the name of _bellicosus_, _fatalis_, or
_mordax_, but only justly so in as much as their war of extermination is
directed exclusively against vegetable products. Their destructive fury
shows itself in the most troublesome fashion, so that nothing is safe
from them; all vegetable material and objects placed on it, such as
boxes, trunks, building timber, paper, or cord, is covered by these
insects with the familiar crust of mud, unless preventive measures are
taken against them, and underneath this the work of destruction goes
forward.[336] Many districts, in which dry branches and withered leaves
or grass cover the ground, thus take on an appearance towards the end of
the rainy season, which Marquardsen describes very accurately, when he
says that they ‘give the impression that they have been exposed to
floods for a long time’.[337] The damage done by the white ants is to
some extent counterbalanced by the fact that during the rains swarms of
these little creatures, which lose their wings at the slightest touch,
are collected as food by the natives.[338] Where ant-hills exist in the
bush they are in a regular proportion with the number of _capparis_
bushes, which thrive in unusual profusion in just such spots; and it is
not impossible that this fact conceals a law of symbiosis.
The strange-looking _Mantidae_ and _Phasmidae_ do not leave one in any
doubt as to their existence in Bornu. The number of locusts also,
including the _Acridiae_ with brightly coloured under-wings, is legion,
they start up wherever one goes. Rohlfs observed clouds of these
creatures moving from north to south and taking hours to pass a given
point.[339] At the beginning of the rains appear the _Gryllus_ species,
with few varieties but in large numbers. These are the insects which
make themselves chiefly perceptible to one’s hearing; in fact, one large
species gives out such a shrill note, that one’s ears ache if standing
in the vicinity of this musical insect. On the other hand, the cricket,
the most noisy insect in the primaeval forest region, is remarkably rare
in Bornu, the _Fulgoridae_ also are not common; the above-mentioned
distinction between the dry and rainy seasons may not suit them.
Bugs too show a great variety of forms. Whilst many of them are
deceptively like a withered leaf, others resemble the beetle species in
form and markings; and the _Reduviini_ administer an irritating bite
when touched. A species of bed-bug is also found, and this kind of
vermin is very widely distributed.
In hollow trees are to be found centipedes, _Scolopendra_, which are
dreaded on account of their bite, but the giant ‘Julus’ species, or
millepede, as thick as a man’s finger, which lives in similar places, is
perfectly harmless.