ROAD-MAKING ANIMALS.
IN a note on trespass by animals the editor of Country Life states that the Welsh mountain sheep have obtained legal recognition of their capacity to distinguish boundaries and assert rights of way. On certain farms the flocks know the boundaries of their mountain pastures, and presumably transmit this knowledge to their lambs. They also maintain their rights against intruders, and if they meet trespassing sheep on the paths which generations of flocks have worn on the mountain side, they do battle for the right
of way, and if possible knock the intruders down the hill. This sense of locality augments the value of flocks bred on these hills, and the enhanced value was settled at Dolgelly Assizes as half-a-crown per sheep.
We should expect this assertion of rights of way by sheep, though their knowledge of boundaries is more difficult to account for. Sheep have for unknown ages been the great pathmakers on mountains and downs, and have left their mark on the faces of the everlasting hills. The sheep walks are only made intentionally in so far that the flocks having once settled which is the shortest, easiest, and best route across these roadless hills, never seem to abandon what their reason has decided to be the best.
Out on the bills these animals are almost in their primitive condition before domestication, and not the least interesting feature of their conduct in this relapse to the wild life is that, in spite of the highly artificial conditions in which they live to- day, they retain the primitive instincts of their race. That this "peremptory and path-keeping" impulse is part of their early instinct is clear from an account of the habits of the musk-ox recently written by the Times correspondent in Canada. The musk-ox, the ovibos, is as much akin to the sheep as to the bovidx, and in habits more like what we imagine the unde- scended great original of our sheep was than are the wild sheep of to-day. It naturally assembles in great flocks, and is migratory, just as all the domesticated flocks of Spain are, and those of Thrace and the Caspian steppe. These flocks always return from the barren lands in the Far North by the same road and cross rivers by the same fords. Nothing but too per- sistent slaughter at these points by the Indians who beset them induces them to desert their ancient highways. Pictures and anecdotes of the migrations of these animals, and of the bison in former days, represent them as moving on a broad front across the prairie or tundra. The examples of all moving multitudes suggest that this was not their usual formation on the march, and their roads prove that they moved on a narrow front or in file. On the North American prairie, though the bison are extinct, the bison roads still remain, as evidence after the destruction of a species, of some part of its habits. These " trails " are paths worn on the prairie, nearly all running due north and south (the line of the old migration of the herds), like gigantic rabbit tracks. They are hard, the grass on them is green and short, and, if followed, they generally lead near water, to which a diverging track runs from the highway.
It is pleasant to reconstruct in fancy the life on this great animal highway, before the Indian invented the arrow to destroy and torment the moving tribes of beasts. Doubtless, in their unresponsive way, the creatures felt the usual emotions of travellers on a known and pleasant road, looked forward to their halts for food, or detours for water and bathing, and recognised or longed for pastures and retreats -which they had visited yearly as their manes grew shaggier and their frames more ponderous and robust. With the sheep tracks and the buffalo and musk - ox trails may be compared the main roads used by very many graminivorous animals, from those which the hippopotamus cuts through the gigantic reeds fringing African rivers to the hare and rabbit highways on our downs. The main roads of the hares over hills are almost as permanent as the sheep tracks, and must not be confused with their paths to temporary feeding- places or the shelter of crops. In the same way the regular step terraces on the sides of chalk downs, though often made by sheep, are not roads, but feeding-places. As a sheep walks on a steep slope it always grazes on the ground on the side above it. Its neck would not reach that on the lower side. Consequently sheep work backwards and forwards on such slopes, like a reaping machine, taking about a "neck's length" in width each time. This measurement will be found to correspond pretty accurately with the steps on sheep-downs. Field-voles make their roads by sinking cuttings, trapdoor-spiders make gates, and other spiders form suspension-bridges ; but no animal has yet thought of forming an embankment, on which to run a road over wet places, or of building elevated roads, though arboreal creatures are very ingenious in making use of the interlacing limbs of trees for travelling on, and have regular highways from tree to tree.
Even in so simple a matter as road-making there is room for diversity in the motives of the constructors. It will be remembered that among the items of expenditure debited to the account of the firm of brigands directed by the Ea des Montagnes was that of mending the road to Thebes. It had so fallen out of repair that travellers declined to use it, and "business" in this part of his dominions had fallen off. Though not rivalling the powers of foresight possessed by Hadgi Stavros, some animals do put their roads to uses more complex than mere ease of travel. The most sinister purpose for which a seeming roadway is constructed is devised by certain spiders. The species in question frequent sunny heaths, commons, and furze brakes, and select by preference some portion of ground which has been trenched by a field-vole or mole. Frequently these animals make a half-burrow or open excavation,—the former by biting the lower stems and roots of the rough grasses away, and the latter by tunnelling with their backs level with the surface. These open trenches, as the vegetation wears away from above, are occupied by big spiders, which cover the bottom with curving sheets of web woven close like silk. At the end, perhaps 4 in. or 5 in. from the beginning of the trap, they form a continuous, funnel- shaped arch of web, in which they lie hidden. Grains of earth and seeds of grasses fall on to the open trap, which looks like a nice even little road, leading to a hole. Insects of many kinds see this smooth, groove-like path, and attempting to run along it, are entangled, and then pounced upon by the spider. Even a mouse is embarrassed if it is frightened into one of these trammel-roads hung with " toils " of web. Great numbers of industrial insects make paths for use on expeditions which involve the transport of all kinds of loads. But it would be difficult to name a single instance in which they consciously improve the road to facilitate traffic. The roofed paths of many African ants are not rationally designed for this purpose. The roof is mainly intended to keep off the sun, and to enable the creatures to work in the darkness or twilight, which seems a necessary condition for their activities. It has also a secondary and important use in protecting them from the attacks of birds. But ants in general are bad engineers in the road-making department. They do not clear away obstacles, but climb over or round them, and though able and willing to combine, do not seem to realise that co-operative road-clearing would help the community in general. The late Professor Drum- mond noted the same idiosyncrasy among the natives of Central Africa. Thin, narrow little footpaths cover the whole central continent, like rabbit tracks, but even a moderate-sized stone or a bush is left in situ. No one clears away the obstacle, and the path goes round it.
In contrasting the intelligence of other animals with the activities of insects, those creatures, mainly rodents, which form winter stores of food, and transport this from some dis- tance to the hoard, naturally suggest a parallel. As a rule, the objects which they transport are light and small in size, such as beans, kernels, nuts, and grain. These need no roads for transport, and the paths of the ground squirrels, ham- sters, and mice which carry them are mere tracks. Two rodents do make and improve roads for transport. Rats, when established in buildings, will steal and drag home objects as large as a dumpling, or a big turnip, or potatoes. To drag these to their retreats they will at once, and rapidly, enlarge narrow points in their passages, or gnaw away obstacles. But this is only rough road improvement, and extemporised on special occasions. Beavers, the only warm- blooded animals which habitually do heavy transport by land, provide for all contingencies by cutting "rolling ways," biting off all stumps and obstacles, and do their log. rolling along these towards the water. There is very little doubt that were it at all necessary to their com- fort, other animals would have hit on the same ex- pedients. Thus beavers have three kinds of roads, their ordinary tracks near the water, their canals, and the log-rolling roads. This is quite in accordance with the very high degree of their social development as compared with other animals. Variety of roads is a mark of pro- gress among the beasts as among men. Even in Europe there are many degrees of this exhibition of civilisation. The Dutch are the representatives of the beavers among men. On the route from the Hague to Scheveningen, for instance, there lie parallel to each other a carriage road, a canal, a bicycle track, a light railway, side paths regularly, constructed, and in places little tracks or "Katz-passen made by trespassers.
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