Ethan Walker 
Hooves are specialized structures at the ends of mammal digits that help support body weight, resist wear, grip the ground, and transfer forces between the limb and the surface below. They are made partly from tough keratinized tissue, but a hoof is not simply a giant toenail. Beneath and around the visible outer material are … Read more
Even-toed ungulates are mammals in the broader artiodactyl evolutionary radiation, a group that includes deer, cattle, bison, sheep, goats, many antelopes, giraffes, camels, llamas, pigs, peccaries, hippos, pronghorn, chevrotains, musk deer, and their relatives. The name “even-toed” comes from a characteristic foot plan in which the main axis usually runs between the third and fourth … Read more
Odd-toed ungulates are mammals in the order Perissodactyla, a living lineage that includes horses, zebras, wild asses, rhinoceroses, and tapirs. The name means “odd-toed,” but the defining feature is more precise than simply counting toes: the main axis of the foot passes through the third digit, a pattern called mesaxonic. That shared foot plan links … Read more
The main difference between even-toed and odd-toed ungulates is not simply how many toes you can see. It is the structural axis of the foot. In terrestrial even-toed ungulates, the main weight-bearing axis typically runs between digits III and IV, a pattern called paraxonic. In odd-toed ungulates, or perissodactyls, the main axis runs through digit … Read more
A hoofed mammal is, in everyday biological language, a mammal whose feet are specialized for supporting body weight through one or more modified digits capped by hoof-like keratinized structures. These mammals are often called ungulates. Horses, zebras, rhinos, tapirs, deer, bison, giraffes, camels, pigs, hippos, and pronghorn are familiar examples. The simple definition is useful, … Read more
Hoofed mammals include many of the world’s most familiar large land mammals, from horses, zebras, deer, and bison to giraffes, camels, rhinos, tapirs, pigs, hippos, and pronghorn. They are often called ungulates, a convenient biological term for mammals associated with hoof-like, weight-bearing feet. The label is useful, but it does not describe one simple modern … Read more
Rodents are important because they connect many parts of ecosystems. They are prey for birds, mammals, reptiles, and other predators; they consume and move seeds; they dig through soil; they eat vegetation; they disperse fungal spores; and some species physically reshape habitats. A mouse, prairie dog, squirrel, beaver, and capybara may all be rodents, but … Read more
Rodents live in an extraordinary range of environments, from tropical forests and temperate woodlands to grasslands, deserts, mountains, wetlands, farms, and cities. Some spend most of their lives in trees, others underground, and a few are strongly associated with freshwater. Their success comes not from one universal lifestyle, but from many different combinations of body … Read more
Rodent social behavior ranges from strongly solitary territorial living to stable family groups, large colonies, pair bonds, communal nesting, and unusually cooperative systems. A mountain beaver may spend much of its adult life alone, a prairie vole can form a selective pair bond, beavers live in family groups, prairie dogs organize themselves into territorial family … Read more
Some rodents store food for later, but they do not all do it in the same way. A squirrel may bury individual nuts across dozens or hundreds of locations, while another rodent may concentrate food inside a burrow chamber. Kangaroo rats can carry seeds in cheek pouches before placing them in caches, and hamsters may … Read more
