The closest living relatives of dolphins today are the even toed ungulates such as camels and cows with the humble hippopotamus being the closest living relative. The origin of dolphins and the origin of whales in general is the subject of much debate.
Whales, dolphins, and porpoises together constitute the Cetacea (English: cetaceans). All modern Cetacea live in water and cannot survive out of the water.
Did dolphins evolve from wolves?
The early dolphins were smaller and believed to have consumed small fish as well as various organisms in the water. The older theory is that the evolution was of whales, and they came from ancestors of hoofed land animals that were very similar to wolves and even-toed ungulates.
What are similar to dolphins?
Porpoises and dolphins are both members of the same scientific order, Cetacea. Cetacea includes all whales, which are relatives of dolphins and porpoises. Dolphins and porpoises are also both members of the same scientific suborder, Odontoceti, which includes all of the toothed whales.
Is an orca a dolphin or porpoise?
The orca, or killer whale, for example, is actually the largest member of the dolphin family. Dolphins are by far more prevalent than porpoises. Most scientists agree that there are 32 dolphin species (plus five closely related species of river dolphin) and only six porpoise species.
Do dolphins lungs?
Dolphins are mammals, not fish. Unlike fish, who breathe through gills, dolphins breathe air using lungs. Dolphins must make frequent trips to the surface of the water to catch a breath. The blowhole on top of a dolphins head acts as a nose, making it easy for the dolphin to surface for air.
Can dolphins drown?
It is actually rare for a marine mammal to drown, as they wont inhale underwater; but they do suffocate from a lack of air. Being born underwater can cause problems for newborn whale and dolphin calves.