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 tail-flukes of the sperm whale are more flexible than most whale flukes. No whales have bones in their tales (hey, that rhymes!). The skeleton of a whale consists of a skull, a backbone, a rib cage, and a collection of bones that are part of the flipper, but correspond closely to the bones in the human arm and hand.here's a skull, backbone, rib cage, and a bunch of bones that look like arm and hand bones. The wrist and hand like bones are in the flipper. In the picture above, the little bones formerly known as the hind leg, are shown enlarged and outside the body. Normally they are inside the body.