Bears & Other Carnivores [antikvár]

A HALF-TON POLAR BEAR CRAWLS STEALTHILY across an Arctic ice floe, its small eyes fixed on a plump, unsuspecting seal. A pack of timber wolves bounds through the deep snow of a Canadian forest, nimbly avoiding the slashing hooves of an enfeebled old bull moose and closing in for the kill. A group of hyenas races after a herd of zebras on the African savanna, lunging at the legs of a laggard youngster that will soon be their victim. A tiny least weasel, weighing scarcely two ounces, searches furtiyely through a Midwestern meadow, its eyes and ears alert for the telltale signs of a mouse.Each, in its own very different way, is skillfully tracking quarry that through millions of years it has come to pursue and eat. All are predators, animals that live by taking prey; all are carnivores, animals that eat other animals' flesh. In this respect they share a great many traits not only with one another but also with human beings. Men evolved as primitiveand not very skilled hunters eons ago, and many still sit down daily to a meal of animal meat. Unlike men, however, polar bears, wolves, hyenas and weasels must take their steak any way they can find it, defend it from competing predators and sometimes risk their own lives to get it.Bears, wolves-and other wild dogshyenas and weasels make up four groups of carnivores that are related in their evolutionary descent from the miacid, a creature that lived 50 million years ago.They have certain attributes in common. All have keen senses with which to detect their prey, particularly an acute sense of smell that is most marked in wolves and is at least a hundred times more sensitive than that of man. Most are relatively intelligent, resourceful animals with large, well-developed brains. Large-eared, night-prowling animals such as foxes also have fine hearing and eyes constructed to see especially well in the dark. Most have the agility, coupled with speed or strength, to overcome their prey once they have flushed it, as well as jaws, teeth or claws capable of gripping and tearing flesh. Those that rely most heavily on meat in their diet have large daggerlike canine teeth for stabbing and holding, backed up by blade-shaped teeth that chop and shear. Since these animals do not need to chew quantities of vegetable matter for their nourishment, their rear molars are not well developed. Their simple stomachs are designed to handle the easily digested, energy-rich flesh of other animals.Beyond these basic attributes the terrestrial carnivores have branched out widely and at times bewilderingly on the evolutionary tree, each shaped by the particular environment it lives in, the kind of food available and competition from other carnivores. As a result, each has specialized equipment, habits, camouflage and hunting skills. The weasel group, over the course of about 35 million years, has developed a broad variety of highly differentiated species. Mink and river otters, for instance, live near lakes and streams and can swim and dive expertly in pursuit of muskrats or fish; others, like martens and fishers, can climb quickly and leap from limb to limb to chase squirrels through the trees.Brown bear and cub in Alaska