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.
1 A thick layer of blubber just under a whale's skin helps insulates a whale from heat loss. There is a heat gradient from the body core, through the blubber, to the skin. 2  Blubber tissue is composed of fat cells and fibrous connective tissue.  The blubber layer can reach a thickness of 50 cm (20 in.) on a bowhead whale.