TOP 10 ANIMALS WITH THE LONGEST GESTATION PERIOD 

Did you know that the African Elephant has the longest gestation period among land mammals, as it can carry its young for between 18 to 22 months before giving birth?

Humans have a relatively long gestation period compared to the rest of the animal kingdom, but a few animals go even further. The size of the offspring is usually a determining factor, but not all lengthy gestations end with a big baby. Here is a list of the animals with the most prolonged gestation periods.

1. AFRICAN ELEPHANT

Elephants have the longest gestation period of all mammals, carrying their young for 18 to 22 months before giving birth.... Since elephants are the largest living and biggest-brained land animals in the world, there's a lot of development for elephants to do in the womb.

2. MANATEES

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...

3. CAMELS 

Camels have a gestation period of 13 to 15 months. The month in which conception occurred can shift the birthdate, with November conceptions pushing the birth 18 days longer than a May conception. Other camelids, such as llamas, also have a long gestation period—about 330 days (11 months).

4. GIRAFFES

Giraffes have gestation periods anywhere from 400 to 460 days (13-15 months). Despite being the tallest land animal in the world, the mother gives birth standing up.

5. VELVET WORM

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.

6. RHINOCEROS

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 15 to 18 months, depending on the species.

7. WALRUSES

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. Walruses also have the lowest reproductive rate of any pinniped.

8. WHALES AND DOLPHINS

Whales and dolphins are known for their high intelligence, complex societies, and peaceful personalities. Although all species have different gestation periods, orcas have the longest period among dolphins at about 17 months. Some sperm whales have been known to carry their young for up to 19 months.

9. BLACK ALPINE SALAMANDERS

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.

10. SHARKS 

Pregnancy length can vary significantly by species. The spiny dogfish shark can carry young for about two years, while basking sharks can do so for as long as three years. The frilled shark can wait 3.5 years before giving birth.

Source:

https://www.treehugger.com/animals-with-the-longest-gestation-period-4869368