Zoology: Bones

The bottlenose dolphin is found across the world in temperate and tropical waters. The bones of the bottlenose dolphin's pectoral fin are homologous (having the same evolutionary ancestry) to the bones of the human arm or the forelimbs of other land mammals. While the dolphin's pectoral flipper, which is used for steering as well as touching other dolphins, may have different functions than the human arm, its skeletal make-up is basically the same. However, the bones that are comparable to the humerus, ulna and radius of the human are foreshortened in the dolphin. The dolphin's flipper bones are firmly held together by connective tissue and cartilage. The forelimbs of the manatee, in contrast, are less rigid.
16" L x 5 ½" W x 2 ½" H / 41 cm x 14 cm x 6.5 cm