Mammals Morphology

Mammals are far more diverse in size than any other class of vertebrates, ranging from tiny shrews and bats to the biggest animal that ever lived, the blue whale. Mammals are also far more diverse in form and appearance than birds and are arguably more diverse than living reptiles and amphibians (though prehistoric reptiles were very diverse as well). Comparing mammals with fish is difficult.

Most mammals are covered with fur, notable exceptions being many marine mammals (cetaceans and sirenians), the naked mole rat and humans.

In general, mammals aren’t as brightly coloured as birds; the dominant colours are brown, gray, black and white.

Many species bear ornamentation in the form of tufts of hair (e.g. the mane of a horse or zebra) or distinctive colour patterns. Of course, colour patterns can also serve as camouflage (e.g. a zebra’s black-and-white stripes).

Some ungulates (hoofed mammals) have often spectacular horns or antlers that serve as weapons and/or in display.

In contrast to reptiles and amphibians, there are no limbless mammals. The only species without legs are marine mammals in the orders Cetacea (whales and dolphins) and Sirenia (manatees and sea cows), along with pinnipeds (seals and sea lions), in which legs have evolved into flippers.

The only mammals with just two legs are bats, which are also the only mammals with wings. However, some primates could be argued to have just two legs, depending on how one defines leg. For example, humans are said to have two legs and two arms.

Most terrestrial mammals have feet that can be described as unguligrade, digitigrade or plantigrade. Mammals with hooves are termed unguligrade, while cats and dogs are examples of digitigrade mammals. Plantigrade mammals walk “flat-footed,” including bears, porcupines and humans.

Civil Engineering