how many dolphins are born at a time
Dolphin Dolphin copulation happens belly to belly; though many species engage in lengthy foreplay, the actual act is usually brief, but may be repeated several times within a short timespan.[67] The gestation period varies with species; for the small Tucuxi dolphin, this period is around 11 to 12 months,[68] while for the orca, the gestation period is around 17 months.[69] Typically dolphins give birth to a single calf, which is, unlike most other mammals, born tail first in most cases.[70] They usually become sexually active at a young age, even before reaching sexual maturity.[67] The age of sexual maturity varies by species and gender.[71]
Porpoise Porpoises are a group of fully aquatic marine mammals that are sometimes referred to as mereswine, all of which are classified under the family Phocoenidae, parvorder Odontoceti (toothed whales). There are six extant species of porpoise. They are small toothed whales that are very closely related to oceanic dolphins. The most obvious visible difference between the two groups is that porpoises have shorter beaks and flattened, spade-shaped teeth distinct from the conical teeth of dolphins. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates, and their closest living relatives are the hippopotamuses, having diverged from them about 40 million years ago.