Adaptations and Biology of Birds, Reptiles, and Mammals

Reptilia

Saltwater crocodile

The saltwater crocodile can live in fresh water, salt water or brackish (mixed) water. If it is living in salty water, its kidneys and tongue allows the excretions of salt. It has eyes and nostrils high up on its head and a broad tail with webbed feet for swimming. It feeds on almost any meat it can get. Animals that live in the water and near the water may/will become food for the saltwater crocs - even people!! A hunting tactic that it has developed includes the art of camouflage - where it stealthily moves underwater with only its nostrils above the surface. Besides the saltwater crocodile's art of stalking its prey, it also has its elusive death roll that it uses in order to tear flesh which gives an instantaneous death when clamped between both jaws.

Aves
Penguins

Penguins are superbly adapted to an aquatic life. Their wings have become flippers - and contain a denser bone material that is useless for flight in the air, in water however, penguins are astonishingly agile. Within the smooth plumage a layer of air is preserved, ensuring buoyancy. The air layer also helps insulate the birds in cold waters. On land, penguins use their tails and wings to maintain balance for their upright stance. All penguins are countershaded - that is, they have a white underside and a dark (mostly black) upperside. This is for camouflage. A predator looking up from below (such as an orca or a leopard seal) has difficulty distinguishing between a white penguin belly and the reflective water surface. The dark plumage on their backs camouflages them from above. Diving penguins reach 6 to 12 km/h (3.7 to 7.5 mph), though there are reports of velocities of 27 km/h (17 mph) (which are more realistic in the case of startled flight). The small penguins do not usually dive deep; they catch their prey near the surface in dives that normally last only one or two minutes. Larger penguins can dive deep in case of need. Dives of the large Emperor Penguin have been recorded which reach a depth of 565 m (1870 ft) and last up to 22 minutes. Penguins either waddle on their feet or slide on their bellies across the snow, this allows them to conserve energy and move relatively fast at the same time. They also jump, with both feet together. Penguins have an excellent sense of hearing. Their eyes are adapted for underwater vision, and are their primary means of locating prey and avoiding predators; in air, conversely, they are nearsighted. Their sense of smell has not been researched so far. They are able to drink salt water safely because their supraorbital gland filters excess salt from the bloodstream. The salt is excreted in a concentrated fluid from the nasal passages.

Mammalia
Baleen Whale

Like all mammals, whales: breathe air into lungs, are warm-blooded, feed their young milk from mammary glands, and have some hair. The body is fusiform, resembling the streamlined form of a fish. The forelimbs, also called flippers, are paddle-shaped. The end of the tail fins provide propulsion by vertical movement. Most species of whales bear a fin on their backs known as a dorsal fin. Beneath the skin lies a layer of fat. It serves as an energy reservoir and also as insulation. Whales have a four-chambered heart. The neck vertebrae are fused in most whales, which provides stability during swimming at the expense of flexibility. Whales breathe through blow holes located on the top of the head so the animal can remain submerged. Whales have a unique respiratory system which allows them to stay underwater for a long period of time without needing to re-surface to breathe. There are similarities between the ears of whales and humans, whales’ ears have specific adaptations to their underwater environment. In humans, the middle ear works as an impedance matcher between the outside air’s low-impedance and the cochlear fluid’s high-impedance. In aquatic mammals such as whales, however, there is no great difference between the outer and inner environments. Instead of sound passing through outer ear to middle ear, whales receive sound through their lower jaw.