Tetrapods

Viviparous

Bringing forth living young rather than eggs, as most mammals and some reptiles and fishes.

Endothermic

Warm-blooded

Exothermic

Cold-blooded

Aves

A class of vertebrates comprising the birds.

Pinnipedia

A group of semi-aquatic marine mammals that include sea lions, fur seals, true seals and the walrus.

Dive Reflex

A reflex in mammals which optimizes respiration to allow staying underwater for extended periods of time.

Sirenia

An order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters.

Cetacea

An order of marine mammals that comprises the whales, dolphins, and porpoises.

Tetrapod

Any vertebrate having four limbs or, as in the snake and whale, having had four-limbed ancestors.

Myoglobin

Hemoglobin of muscle, weighing less and carrying more oxygen and less carbon monoxide than blood hemoglobin.

Ovoviviparous

Producing eggs that are hatched within the body, so that the young are born alive but without placental attachment, as certain reptiles or fishes.

Oviparous

Producing eggs that mature and hatch after being expelled from the body, as birds, most reptiles and fishes, and the monotremes.

Mammalia

The class comprising the mammals.

Reptilia

The class comprising the reptiles.

Migration

To pass periodically from one region or climate to another, as certain birds, fishes, and animals.