Marsupial Mammals What is a Marsupial? Marsupials are a group of mammals that have an external pouch located on their mother's abdomen in which they carry their young. Most marsupials live in Australia, where they have evolved into some unique and unusual animals. Marsupials range in size from the 1.8 meter tall red kangaroo which weighs 90kgs to the tiny, shrew-like long-tailed planigale which is just 6 cm in length and weighs only 4 gms.
Whale ribs loosely articulate with their thoracic vertebrae at the proximal end, but they do not form a rigid rib cage. This adaptation allows the chest to compress during deep dives as opposed to resisting the force of water pressure.
A beaked whale is any of at least 22 species of small whale in the family Ziphiidae. They are one of the least-known families of large mammals: several species have only been described in the last two decades, and it is entirely possible that more remain as yet undiscovered.