12 Animals With the Longest Gestation Period

Gorilla mother and baby
Photo: Sharon Morris/Shutterstock

We owe a lot to our mothers. They carried us for about nine months before giving birth. Human mothers have a relatively long gestation period compared to the rest of the animal kingdom, but a few animal mothers go even further. Here's our list of the animals with the longest gestation periods.

1
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Manatees

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You might not know if a portly manatee is pregnant simply by looking at the animal, but this gentle giant carries its young for nearly 13 months. Lounging around in the water all day helps to relieve some of the extra weight, but a manatee mother is still owed plenty of respect for her patience.

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Camels

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Camels are known for their stubborn and crabbish personalities, but consider this: Camels have a gestation period of 13-14 months or around 410 days. Other camelids, such as llamas, also have a long gestation period — about 330 days.

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Giraffes

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Giraffes have gestation periods anywhere from 400 to 460 days. Despite being the tallest land animal in the world, the mother gives birth standing up — so the baby needs to be big enough to brace for a long fall. (Interestingly, the fall is typically what bursts the embryonic sack.) With lions and other predators abound, the world is a dangerous place for baby giraffes when they first come into the world — part of the reason for the long delay.

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Velvet worm

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Not all animals with long gestation periods are large mammals. There are some worm-like animals that bear live young, including the velvet worm. This bizarre-looking creature carries its young for as long as 15 months. Despite the name, they aren't true worms and they aren't made of velvet. Their bodies are covered with sensory hairs, which gives them a velvety appearance.

They are considered close relatives of both arthropods (spiders and insects) and true worms (like the earthworm) — making them especially interesting to paleontologists.

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Rhinos

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It might not come as a surprise that rhinos — because of their sheer size — are next on the list with a gestation period of about 450 days. This long gestation period is also an obstacle to replenishing the population. All five species of rhinoceros are endangered or considered vulnerable, and three out of the five are considered critically endangered.

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Walruses

Photo: U.S. Geological Survey [public domain]/Flickr

Walruses have the longest gestation period of all pinnipeds (a group of mammals that includes seals and sea lions), carrying their young for as long as 15 to 16 months. (Seal and sea lion mothers are also dedicated, carrying their offspring for about 330 and 350 days respectively.) Walruses also have the lowest reproductive rate of any pinniped.

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Whales and dolphins

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Whales and dolphins, also known as cetaceans, are known for their high intelligence, complex societies and peaceful personalities — it's no surprise that they also take a lot of care in developing their young. Although all species have different gestation periods, orcas have the longest period among dolphins (at about 17 months). Some sperm whales — the largest living predators — have been known to carry their young for up to 19 months.

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Elephants

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Elephants have the longest gestation period of all mammals, carrying their young for nearly two years before giving birth. Long developmental periods are common among highly intelligent animals. Since elephants are the largest living and biggest-brained land animal in the world, there's a lot of developing for elephants to do in the womb.

9
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Black alpine salamanders

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Black alpine salamanders are amphibians that live in the Central and Eastern Alps and give birth to live young. Their pregnancies can last from two to three years, depending on the altitude at which the salamanders live. They typically bear two fully developed young. This salamander's life expectancy has been estimated to last from 10 to even 20 years.

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Sharks

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Unlike most fish, sharks are K-selected reproducers — meaning they produce a small number of well-developed young as opposed to a large number of poorly developed young. Pregnancy length can vary greatly by species. The spiny dogfish shark can carry young for about two years, while basking sharks can carry them for as long as three years, and the frilled shark can wait 3.5 years before giving birth.

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Tapirs

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A tapir may appear to be a cross between a pig and an anteater, but it's actually most closely related to horses and rhinos and shares a similarly long gestation period. A tapir calf is born after 13 months in the womb. Newborns have special brown- and beige-striped markings that help camouflage them from predators, but the pattern fades after a few months when the young tapir becomes more mobile.

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Donkeys

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A female donkey, known as a jenny or a mare, typically gives birth to one foal after about a year after mating, but some pregnancies can last nearly 14 months.