CHAPTER XXXV

INSECTIVORA--HEDGEHOGS, MOLES AND SHREWS

Again we have to deal with the scattered and feeble relics of a once important race; but that was long ago, even as geologists use the word long, for the order of insectivores (Insectivora) may be traced backward to the very earliest, hardly identifiable, fossil remains of mammalian pioneers in a reptilian world. These are known mainly by their dentition, which in this order is characterized by weak canines, small sharp incisors, and all the back teeth small, with many points and sharp edges designed for cutting through the shards of insects, shells of eggs, snail shells and the like, rather than for chewing. They had become, even in the Eocene period, a numerous and varied group, including arboreal, terrestrial, and aquatic types, some of considerable size, besides many minute forms comparable to the moles and shrews of the present day, and very likely ancestral to them. At the beginning of the Tertiary, they are indistinguishable from the earlier of the creodonts, but these rapidly developed into powerful beasts, while the insectivores retained more nearly their ancient ways, and in the later Tertiary diminished rapidly in numbers and variety. To-day only a few survivors are left, protected from their enemies by armor, as in the case of the hedgehogs; by a subterranean mode of life, as the moles; by their agility, minute size, and unpleasant odor and taste, as are the shrews; or, finally, by their exile in some remote corner of the world, where enemies are few. Thus we find remnants of families so widely separated as Madagascar and Cuba--the same disintegration that has overtaken many another ancient and decadent tribe; and their organization is so generalized that systemists find it difficult to place them in any serial arrangement with other orders; the big Malayan kaguan, for instance, which lives in trees and looks and behaves like a flying squirrel, was long classed with the lemurs.

Oldest of the existing insectivores, and nearest the original type, is the hedgehog of Europe, which, when rolled up, presents to its enemy a living chestnut bur of stiff spines hardly bigger than a baseball. All day it lies curled up asleep in an underground nest (where in winter it hibernates), and wanders about at night hunting for insects, worms, snails, slugs and the like, and savagely attacking and killing every viper it comes across--a valuable little animal, preserved by every intelligent gardener. Next to it are the lively little "tupaias," or tree shrews of the East, and the queer, long-nosed, kangaroo-shaped jumping shrews of the deserts. A rarer oddity is the river shrew of West Africa, looking and acting like a miniature muskrat. Then there are the "almiquis" of Cuba and Haiti, which suggest small, ground-traveling opossums, whose nearest relatives are the spiny "tenrecs" of Madagascar.

More familiar to us are the moles and shrews of northern countries. Moles are chiefly remarkable for the adaptation of their frames to the requirements of an underground existence, in which they must travel and seek their food, and not merely make their nightly home in burrows. This has brought about an alteration of the forelimbs into digging tools of really gigantic power when we consider the size of the animal, and a strength of shoulders that enables them to bore their way through loose soil without shoveling it out, save at long intervals. Everybody knows the upheaved ridges that mark their paths on the lawn as they move here and there beneath the grass roots in search of grubs and earthworms. One of our common species, preferring wet meadows to the uplands, is the star-nosed mole, whose muzzle is encircled by pink tentacles, very sensitive, which give it its name.

Highest in rank among insectivores, though least in size, are the shrews, one of which, our Cooper's shrew, is the smallest of all mammals. They are mouselike in appearance, but with long, flexible, much bewhiskered snouts, and are ceaselessly active, wandering about underneath leaves, old grass, and logs, and boring their way into loose loam or the punky wood of decayed stumps, in search of earthworms, grubs, beetles, slugs, and similar prey, including young mice and the fledglings of ground-nesting birds, and varying this fare by bites from soft-shelled beechnuts, tuberous roots, etc. They are quick of hearing, bold, pugnacious, and fierce, often killing and eating other shrews; difficult to keep alive in captivity, utterly untamable, and easily frightened to death.