Female elephants can bear their children for 18 to 22 months before giving birth, making them the longest-carrying mammals.Highly intellectual animals tend to have extended periods of growth. 

Elephants

Camels have a 13- to 15-month gestation period, despite their stubbornness. The month of conception can alter the birthday, with November conceptions pushing the birth 18 days later than May. 330 days is also a long gestation period for llamas (11 months).

Camels

Giraffes gestate about 400-460 days (13-15 months).Despite being the tallest land animal, the mother gives birth standing up, so the baby must be big enough to survive a fall. 

Giraffes

Rhinos, because of their size, are next on the list, with a gestation time of 15 to 18 months, depending on the species.This long gestation time slows population growth. All five species of rhinoceros are endangered or vulnerable, and three are highly endangered.

Rhinoceros

Whales and dolphins are famed for their intelligence, complex society, and gentle attitudes, so it's no surprise that they care for their offspring. All species have varied gestation times, but orcas' is 17 months. 

Whales and Dolphins

Unlike other fish, sharks are K-selected reproducers, meaning they produce fewer well-developed pups.Pregnancy length varies by species. The spiny dogfish shark can bear pups for 2 years, whereas basking sharks can do so for 3 years. 

Sharks

A tapir may look like a pig-anteater hybrid, but it's connected to horses and rhinos and has a long gestation time. A 13-month-old tapir calf is born. Newborns feature brown-and-beige-striped patterns that assist disguise them from predators.

Tapirs

The average gestation period for a female donkey, also known as a jenny or a mare, is 12 months, but in extreme cases it can extend as long as 14 months. Jenny can go into foal heat anywhere from 5 to 13 days after giving birth to a foal, allowing her to be bred again.

Donkeys

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