CHAPTER VII

THE INDUSTRIES OF ANIMALS

1. Hunting-2. Shepherding-3. Storing-4. Making of homes— 5. Other instances of constructive skill-6. Movements.

VERY early in the history of the human race there must have begun a differentiation of modes of livelihood. In certain places and among men of certain types, hunting and fishing became habitual arts. Elsewhere and among men of other mood pastoral life began, and the almost lost art of domestication had its early triumphs. Along a third line, but of course with interactions, agriculture developed, and with this we may reasonably associate the foundation of stable homesteads. And around the primary occupations of hunting and fishing, shepherding in the wide sense, and cultivating the soil arose more specialised activities, with division of labour between man and woman and between man and man.

Now, the activities of men suggest a convenient arrangement for those practised by animals. For here again there are hunters and fishers-beasts of prey of all kinds -pursuing the chase with diverse degrees of art; shepherds, too, for some ants use the aphides as cows; and farmers without doubt, if we use the word in a sense wide enough to include those who collect, modify, and store the various fruits of the earth.

In illustrating these industries, we shall follow a charming volume by Frédéric Houssay, Les Industries des Animaux, Paris, 1890 (trans. London).

1. Hunting. Of this primary activity there are many kinds. The crocodile lies in wait by the water's edge, the python hangs like a liana from the tree, the octopus

lurks in a nook among the rocks, and the larval ant-lion (Myrmeleon) digs in the sand a pitfall for unwary insects. The angler-fish (Lophius piscatorius) is somewhat protectively coloured as he lies on the sand among the seaweeds; on his back three filaments dangle, and possibly suggest worms to curious little fishes, which, venturing near, are engulfed in the angler's wide gape, and firmly gripped by jaws with backward-bending teeth. Many animals prowl about in search of easy prey-eggs of birds, sleeping beasts, and small creatures like white ants; others would be burglars, like the Death's Head Moth (Sphinx atropos) who seeks to slink into the homes of the bees; others are full of wiles, witness the cunning fox and the wide-awake crow. Many, however, are hunters by open profession, notably the carnivorous birds and mammals.

Among these hunters there are many strange exploits; such, for instance, as that of a large spider which landed a small fish. The ins and outs of their ways are most interesting, especially to the student of comparative psychology. Think of the Indian Toxotes, a fish which squirts drops of water on insects and brings them down most effectively; several birds which let shells drop from a height, e.g. the Greek eagle (Gypaëtos barbatus), which killed Eschylus by letting a tortoise drop on his head, and the rooks which break freshwater mussels by letting them fall among the stones; the grey-shrike (Lanius excubitor), which spikes its victims on thorns; and, strangest perhaps, the slave-making expeditions of the Amazon ants. All strength and wiles notwithstanding, the chase is often by no means easy; the hare grows swift as well as the fox, many grow cautious like trout in a much-fished stream, scouts and sentinels are often utilised, the weak combine against the strong, and the victims of even the strong carnivores often show fight valiantly.

2. Shepherding. Although the ants are the only animals which show a pastoral habit in any perfection, and that only in certain species (e.g. Lasius niger and Lasius brunneus), the fact is one about which we may

profitably exercise our minds. Let us follow Espinas's admirable discussion of the subject.

We may begin with the simple association of ant and aphides as commensals cating at the same bountiful table. But as ants discovered that the aphides were overflowing with sweetness, they formed the habit of licking them, the aphides submitting with passive enjoyment. Moreover, as the ants nesting near the foot of a tree covered with aphides would resent that others should invade their preserves, it is not surprising to find that they should continue their earthen tunnels up the stem and branches, and should eventually build an aerial stable for some of their cattle. Thither also they transport some of their own larvæ to be sunned, and as they carried these back again when the rain fell, they would surely not require the assistance of an abstract idea to prompt them to take some aphides also downstairs. Or perhaps it is enough to suppose that the aphides, by no means objecting to the ants' attentions, did not require any coaxing to descend the tunnels, and eventually to live in the cellars of the nests, where they feed comfortably on roots, and are sheltered from the bad weather of autumn. In autumn the aphides lay eggs in the cellars to which they have been brought by force or coaxing or otherwise, and these eggs the ants take care of, putting them in safe cradles, licking them as tenderly as they do those of their own kind. Thus the domestication of aphides by ants is completed.

3. Storing. A beginning of storing may be looked for in activities like those of earthworms, which take leaves down into their burrows, at once making these more comfortable and providing a supply of food for the rainy day. Among insects we find a long inclined plane from the sacred scarabees, common in the Mediterranean region, which roll balls of dung to their holes, and gnaw at them at their leisure for days, to the hive-bees with their exaggerated storing instinct. The famous French entomologist Fabre (who died in 1915 at the age of ninety-two) has described inimitably how the mother scarabee moulds a pear-shaped mass of dung and deposits

at the narrow end an egg which occupies a special hatching chamber and has beside it a special first meal for the emerging grub! The Spanish Copris and some related dung-beetles are among the very few non-social insects with complete metamorphosis in which the mother survives to see the offspring attain the fully formed stage. The ordinary occurrence among the higher orders of insects is that the mother does not survive to see her young in the perfect state. In many cases she never sees her young at all, for she is dead before the eggs are hatched.

There is an evolutionist gratification in studying the storing activities of bees, for they are exhibited in such varied degrees of elaboration by different types. Among the solitary bees the mother makes a store for the brood which she very rarely survives to see; among humblebees the store is begun by the mother but continued by her worker-children, and there are species (beyond British bounds) in which at least a part of the society survives the winter; in tropical species of the bees generically called Melipona and Trigona there are permanent societies but with imperfect combs; in the hivebees we have to do with permanent societies and with perfect combs. The elaborate storing, carried to abnormal exuberance under man's domesticating tutelage, is correlated with surviving the winter, i.e. with permanence, and with the survival of the mothers after the adolescence of their offspring, i.e. with the possibility of social tradition.

As among bees, so among ants, we find all grades from those that do not store at all to those that make a fine art of it. According to recent studies of the common Mediterranean ant, Aphanogaster barbarus, the seeds which are collected are kept for a time dry and are eventually put out in the rain so that they begin to germinate. This has the advantage of bursting the hard seed-coats, and in some cases of starting processes of fermentation. At a certain stage, however, the ants kill the embryo-plant by biting off the radicle or other parts, and the seeds are dried again in the sun. According

to Neger the dried seeds, of some Leguminous plants for instance, are then taken back into the nest and chewed into dough. This is dried once again in the sun in the form of little biscuits, which are eventually put into the cupboard. It is probable that different kinds of seeds receive different treatment, and in some cases it seems that the stored material is not eaten after all, but is used as a culture for moulds (e.g. Aspergillus niger) of which the ants are very fond.

Among backboned animals it is difficult to find convincing instances of storing until we come to birds and mammals. Apart from the numerous birds that store food in their crops, sometimes so exuberantly that they cannot fly, there are some that may be said to lay up nutritive savings outside of themselves. The large Eagle Owl, which occasionally visits Britain, often gathers a huge superfluity of food (including hares and rabbits, poultry and pigeons) for his mate and offspring; and peasants have been known to utilise him as Elijah his ravens. There is an old tale that ptarmigan make stores of buds and berries beneath the snow, but there is no doubt that at least two species of woodpeckers store acorns, sticking them firmly into holes which are bored "for the purpose " in the tree stems. This is all the more interesting if it be true that what the woodpeckers really eat is not the acorn but a kind of grub that develops inside it.

Not a few mammals are in the habit of hiding away surplus food, and it is easy to imagine how this might lead on to a more definite storing instinct such as squirrels exhibit. In a number of different hoards the squirrel hides hazel-nuts, beech-nuts and acorns, and these may be a stand-by in the hard times of winter when the beautiful creature, who is not a true hibernator, is unable to sleep away its hunger, or when the young ones, who remain for a long time in the company of their parents, plead for food. In some mild parts of the country the squirrel's storing instinct seems to remain undeveloped. There are other mammals, such as the marmots, who make their burrows comfortable with