First, no one is sure why we, or any other animal, dream. During the past century, however, scientists have made significant progress in understanding the factors that influence sleep and dreaming.

Almost all marine mammals are carnivores: Think orcas, whales, dolphins, and even walruses and otters. Even baleen whales eat ...

Tusks are a striking feature of many animals -- elephants, hippos, warthogs, walruses -- and are often sought-after by humans. But no birds, fish or reptiles today sport this extreme and ever-growing ...

Animal communication is more than simple signals. Mammals use sounds, expressions, and touch to convey emotions and social ...

From its long, flexible trunk to its loud trumpeting sounds, there’s a lot to admire about an elephant. But how much do you know about these massive creatures? Where do they live? How big can they get ...

From the 20-foot-long jawbones of the filter-feeding blue whale to the short, but bone-crushing, jaws of the hyena and the delicate chin bones of a human, the pair of lower jawbones characteristic of ...