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.
The ribs are a set of twelve bones which form the protective âcageâ of the thorax. They articulate with the vertebral column posteriorly, and terminate anteriorly as cartilage (known as costal cartilage). As part of the bony thorax, the ribs protect the internal thoracic organs. They also have a role in breathing â during chest expansion the ribcage moves to permit lung inflation.