Beavers & Other Rodents [antikvár]

INTRODUCTION After a winter spent in hibernation, this hoary marmot is foraging for food amid a sea of lupines in North America's Mount Rainier National Park. The animal must lay down large reserves of fat to sustain it through the following winter's slumber. Rodents are among the most successful of all mammals, and, in their range and numbers, among those most closely linked to the spread and progress of man. Some of the seventeen hundred or so species that make up the group have followed in the wake of man, taking advantage of newly created habitats and feeding opportunities resulting from farming and urbanization, while others have declined as the human population has grown in size and influence. Some rodents help spread contagious diseases, but by contrast, a few species have become cherished pets. There is even one, the beaver, over which wars have been fought. There is scarcely a terrestrial habitat where rodents of one species or another do not occur. Grasslands are the domain of mice and voles, while forests are home to squirrels and their relatives. Wetland habitats present few problems for these versatile mammals, with beavers, capybaras, and coypus adopting an almost aquatic lifestyle. Marmots living on mountain-tops, gerbils inhabiting deserts, and lemmings proliferating on the arctic tundra—the list goes on and on. Only the open sea and the skies appear to be out of bounds to rodents, although flying squirrels make a valiant attempt at conquering the latter. Although most rodents conform to a rather squat and superficially uniform body plan, the size range seen across the group as a whole is enormous. Some of the smallest mice may weigh just a few grams, while that giant among rodents, the capybara, is the size of a sheep and weighs more than 135 pounds (60 kilograms). The group's size range is also complemented by a varied diet, despite the fact that all rodents share the same basic gnawing method of feeding. Add to this a prodigious reproductive rate and a lifestyle that often involves social as well as sociable behavior, and it is little wonder that rodents have an impact on all our lives.