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.
[Illustration: MANDRILL, MOUTH OPEN TO SNARL
Photos, Elwin R. Sanborn, New York Zoological Society]
[Illustration: GORILLA, SOMEWHAT THOUGHTFUL]
[Illustration: CHIMPANZEES IMITATING SOME OF THE WAYS OF MAN
Photo, Elwin R. Sanborn, New York Zoological Society]