Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals. It is typical for mammals, but also occurs for some non-mammals. Mammals during pregnancy can have one or more gestations at the same time, for example in a multiple birth. 

 

What is the Gestation Period?

The gestation period, in mammals, is the time period between conceptions until birth, during which fetal development takes place in the uterus. It begins when a fertilized male sperm enters the uterus and ends when the fetus leaves the uterus during the birth process. In humans, the gestation period takes approximately nine months.

The gestational period refers to the interval in completed weeks between the first day of the last menstrual period of the mother and the day, month and year of delivery irrespective of whether the product of conception is a live birth or born with no evidence of life (foetal death).

 

Gestation Periods in Different Species

The gestation period is different between mammal species. Some take only a matter of weeks to give birth, whereas others have to wait months. Human mothers have a relatively long gestation period compared to the rest of the animal kingdom, but a few animal mothers go even further. The size of the offspring is usually a determining factor, but not all lengthy gestations end with a big baby.

In the current animal world, the longest gestation period belongs to elephants, where it can last as long as 22 months. On the other hand, the opossum is the shortest at only 12 days. Dogs have a gestation period, on average, of 61 days, with cats and average of 64. However, these figures depend heavily on the breed and size of the animal in question.

 

Gestational Age

Because the actual date of conception is not usually known when measuring pregnancies in mammals such as humans and monkeys, gestational age is often used instead.

Gestational age is measured from the last day a female has a menstrual period and determines the progress of a fetus based on its physical maturity. It is divided into two parts: the embryonic stage, which lasts from week five until week ten, and the fetal stage, which lasts until birth.

 

Top 10 Animals with Longest Gestation Periods

Here’s our list of the top 10 animals with the most prolonged gestation periods:

Rank  Animal             Days

1. Elephant (African)   645

2. Elephant (Asian) 617

3. Whale (sperm) 480–590

4. Rhinoceros (black) 450

5. Giraffe    420–450

6.  Donkey  365

7.  Zebra (Grant’s)  361­-390

8.  Camel (Bactrian)   360-­420

9.  Sea lion (California)  350

10.  Alpaca   335­-366

 

1. Elephant (African) 645

Nothing about elephants is small, and their pregnancies are no exception. Before giving birth to a 110-kilogram calf, mothers carry the fetus for 22 months, the longest gestation period of any mammal.

And whereas most mammals have only one corpus luteum—a temporary gland that controls hormone levels during pregnancy—elephants have as many as 11. Now, by giving 17 elephants blood tests and ultrasound scans throughout their pregnancies, researchers have discovered a key to this remarkable form of motherhood.

Elephants have the longest pregnancy period of any living mammal. If you – or someone you know – have experienced a pregnancy that seemed to go on forever, spare a thought for the elephant. It’s the animal with one of the longest gestation periods of all living mammals: nearly two years.

Elephants are the largest land mammals in the world, so it’s perhaps not surprising that they have the longest pregnancy of any living mammal: African elephants are pregnant for an average of 22 months.

Elephants are highly intelligent mammals – they’re born this way, which takes time.

They also have an impressive brain to show for it: it’s the largest of any land animal, with a structure similar to that of a human brain.

However, it’s three times as large as ours, with three times as many neurons – 250 billion, in fact. They say, ‘an elephant never forgets’, and there’s actually some truth in that saying. Their temporal lobe region (the area responsible for memory) is exceptionally developed, with a greater number of folds, meaning it can store more information.

It allows for retaining details that are vital for elephant survival, such as where to go to find food and water – and how to get there. The matriarch of a herd can lead family members to waterholes by calling up complex mental maps that cover hundreds of kilometres.

Elephants rank alongside dolphins and chimpanzees in terms of levels of intelligence. They’re adept at problem-solving, from piling up blocks to reach food, to using branches and rocks as tools. Their trunks allow them to be dexterous beasts, using them to move and manipulate objects in much the same way that we would use our hands and arms.

They’re one of very few species that understand what pointing means – for example, many dogs understand it, but chimpanzees do not.

Elephants can also recognize themselves in a mirror – another rarity in the animal kingdom, as only the great apes, crows and bottlenose dolphins display the same levels of self-awareness. They demonstrate compassion, too; they help injured members of the herd and show grief when a family member dies. These gentle giants have even known to bury their dead, or cover them with leaves.

And if that wasn’t impressive enough for you, they’re also capable of imitating the sounds of other elephants and even some human words.

 

2. Elephant (Asian) 617

Asian elephants aren’t quite as big as African elephants; they grow to about nine feet tall at the shoulder and weigh around four tons. Like the African elephant, the

Asian elephant has a long trunk, but only males have long tusks. They also have smaller ears than African elephants, and a higher, more pronounced forehead.

An Asian elephant it’s 18 to 22 months. You might think such a long pregnancy is because of what huge creatures they are – but you’d only be partly correct. Baby elephants do develop slowly in the womb because of their physical size but also because of the size of their intellect…

Elephants are among the smartest, largest animals on the planet. With all that size and brain power, it should come as no surprise that making a baby elephant is no easy task.

In fact, elephants have so much developing to do in the womb that they actually have the longest pregnancies of any creature on Earth. That’s right; the elephant gestation period is the longest of any animal, even longer than rhinoceros, blue whales, and humans.

Let’s take a look at just how long an Asian elephant’s gestation period is, and learn a little more about elephants themselves along the way.

There are two extant species of elephants; the African savanna elephant ﴾Loxodonta africana﴿ and the Asian elephant ﴾Elephas maximus﴿. The African elephant is the largest land mammal on Earth, the Asian elephant is slightly smaller. Both elephant gestation periods are extremely long, but the African elephant actually has the longest gestation of any animal in the world. Scientists worked for years to figure out why elephants stay pregnant for so long, and how.

Asian elephants are the largest land mammals in Asia.

Historically, they occupied the entirety of the Indian subcontinent, Asia, Southeast Asia, and the islands of Sumatra and Borneo, among others. Like the African elephant, today’s Asian elephants occupy a tiny fraction of their former homelands. These elephants are primarily forest‐dwelling.

Elephants have the longest gestation of any creature on the planet. Asian elephant gestation periods last anywhere from 18‐22 months, while African elephant gestations last a full 22 months. That’s only two months shy of a two‐year pregnancy! Female elephants begin ovulating between 10‐12 years old, while bulls don’t become sexually mature until around 14 or 15. Often, young bulls do not get the chance to mate until they’re much older and have moved up in the complex social hierarchy.

In general, the bigger the animal, the longer the pregnancy. But, why? Larger animals need more time to grow, and since they’re so large, they also tend to live long lives, which longer pregnancies coincide with. But, that’s not all there is to elephant gestation.

Scientists have found that one of the biggest reasons elephants are pregnant for so long is their big brains. Elephants are born with all the brain cells they’ll ever need, 250 billion of them, to be exact. It takes a lot of development, and time, to grow those big brains. That’s why elephants stay pregnant for at least 18 months, so that, when they’re born, they’re ready to start learning all the things an elephant needs to know to survive.

Elephants are some of the most magnificent, and endangered, creatures on our planet. Their huge bodies and big brains make them especially vulnerable to one thing: extinction. If a herd of elephants disappears, it takes a very long time to replace them.

A single elephant’s gestation lasts nearly two years. After that, calves stay with their mothers for up to ten years, which means the mom only has one calf every 4‐5 years. Elephants are slow to reproduce and take their time growing up, which makes them especially vulnerable to extinction.

 

3. Whale (sperm) 480–590

Whales are marine mammals and share many of the same characteristics that are common among almost all mammals including, the need to breathe air (whales get their oxygen above the surface of the water), being warm-blooded (whales have thick layers of blubber to keep them warm), having hair (some species have hair at birth) and giving birth to their young (not laying eggs as most fish and amphibians do).

Regarding reproduction and length of pregnancy from conception to birth, female whales’ gestation period is very similar to human pregnancy in several ways. 

In fact, it is nearly identical to human birth, with the exception that a whale’s gestation period can last significantly longer than a human’s, depending on the whale’s species.

So how long is the average gestation period for a whale? Depending on the whale species, the average gestation period can range anywhere from 10 – 18 months. While some species can mate throughout the year, the most common time of year for whales to mate/bear offspring is during the colder winter months when various species travel to the warmer tropical environments to mate and give birth.

During mating season, males will compete for the right to mate with the female. The aggression and dominance displayed by the whales will vary from one species to the next, with some males fighting one another or showing off while others appear fairly relaxed and carefree. 

Some species will show their youthfulness by performing various acrobatic stunts, charging one another, and displaying dominance. Other species will sing to attract a mating partner or herd off the female so that competing males have less chance to mate with her.

In a single season, it isn’t uncommon for a female to mate with several males to maximize her chances of bearing a healthy child; in fact, some male species will attempt to wash the competing male’s sperm out by producing significant amounts of their own sperm.

Once the female becomes impregnated, she spends 9 – 18 months developing and carrying her child in her uterus (womb).

After several mating months, these marine mammals will travel back to their feeding grounds until the next mating season.

Gestation period comparisons, to give you a better idea of how long it takes for whales to reproduce once impregnated, here are the gestation periods of various whale species:

·  Minke Whale: 10 months (females average 1 offspring about every 2 years).

·  Narwhal Whale: 14 – 15 months (limited data suggests females bear 1 offspring every 3 years).

·  Sperm Whale: 14 – 16 months (females reproduce every 3 – 6 years).

·  Gray Whale: 13.5 months (data not available)

·  Humpback whale: 11 – 12 months (reproduction occurs every 2 – 3 years).

·  Beluga Whale: 14 – 15 months (females give birth to a single calf every 3 years).

·  Blue Whale: 11 – 12 months (females breed every 2 – 3 years).

·  Killer whale: 15 – 18 months (average is about 17 months).

·  Femalesgive birth every 3 – 5 years.

Read: 6 Types of Farm Animals and Its Characteristic

4. Rhinoceros (black) 450

Few animals on Earth command more respect than the rhinoceros. With its horned head, bulky body, and thundering gait, it is truly the master of its world. Its ancient appearance even leads some to wonder if it’s related to dinosaurs! But with rhino populations dwindling at an alarming rate around the world, their reproductive abilities have taken center stage. How many calves can a rhino birth? How long are rhinos pregnant? And how often can they reproduce? Find out all about this majestic animal below!

The black rhino is the most common and recognizable of the 5 species. Though they remain critically endangered, careful conservation has given them another bid at survival. Conservationists are slowly reintroducing populations of black rhinos to areas they once inhabited, like Rwanda. Only 3 subspecies remain, as scientists have declared the Western black rhino subspecies extinct.

Rhinos are large, horned mammals belonging to the family Rhinocerotidae. Next to the elephant, they are the second biggest land mammal. There are 5 species of rhinos living today, all in Africa and Asia. 

Conservationists classify 4 of these species as Critically Endangered.

Female rhinos are usually ready to mate by 5 years of age, though they may be sexually mature by the age of 3.5 years. To signal their readiness to mate, they whistle, urinate, and defecate. Males leave the females soon after mating.

Rhinos live between 35 and 50 years. White rhinos average a slightly longer lifespan than black rhinos.

Rhinos are pregnant for 15-16 months, though white rhinos may carry for as long as 18 months. Among land mammals, this incredibly long gestation period is second only to that of elephants. These behemoths carry their young for as long as 23 months! Due to their extended pregnancies, rhino populations struggle to recover from poaching and disease.

 

5. Giraffe 420–450

The giraffe is one of the most unique, famous animals on our planet. But, just how long is the giraffe’s gestation period? We’ll answer that question, and many more, here.

First, let’s learn a little more about these incredible creatures. For example, did you know that not only are giraffes the tallest land animals on Earth, but they’re also the largest ruminants in the world?

A ruminant is a hoofed mammal with a chambered stomach, like a sheep or a cow. But, more than that, giraffes are among Earth’s most extraordinary creatures and need to be protected for generations to come.

A giraffe’s gestation lasts anywhere from 400-460 days, or, from 13-15 months. Giraffes do not form monogamous pairs. Rather, dominant males fight each other for mating rights, with winners getting ready access to females.

Female giraffes can get pregnant at any time of the year and come into heat every 15 days. Once their calves are born, mother giraffes tend to stick together in ‘nursery’ herds.

Giraffes almost always have a single calf at a time. However, twins are not unheard of. Giraffes don’t reach sexual maturity until four or five years old for females, and three or four years old for males. 

Male giraffes take no part in the raising or protecting of babies.

Baby giraffes are dependent on their mothers for the first 6-8 months of life. After that, they’re weaned off milk and begin eating solid food. By the time they’re 12-14 months old, they’re fully independent. Female giraffes may have a calf every 1-2 years.

 

6. Donkey 365

Donkeys are pregnant for around 11-14½ months. There are different methods to diagnose an early pregnancy in mares so we recommend that you contact your vet for advice.

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

If that isn’t enough, 5 to 13 days after the birth of the foal, the Jenny can go into what is known as “foal heat” and be bred again.

 

7.  Zebra (Grant’s) 361­-390

There are three different species of zebras in the world – plain zebra,  mountain zebra and grevy’s zebra. Female zebras can breed by the age of three. Based on the species, gestation period can vary. It can last from 10 to 12 months.One zebra foal born at a time. 

Shortly after the birth, a zebra foal could stand and walk. It becomes mature at the age of three. Until then, young zebras live under the protection of the mother.

 
8.  Camel (Bactrian) 360-­420

Camels are known for their stubborn and crabbish personalities, but consider this: 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).

 

9.  Sea lion (California)  350

The gestation period for Australian sea lions is a whopping 17.6 months, the longest gestation of any marine mammal and second longest gestation on the planet (Elephants have the longest). After giving birth, females will typically mate again within seven to 10 days.

The average life span of an Australian sea lion is currently unknown, however believed to be 20 to 25 years. Sea lions at Seal Bay are micro chipped, so with the program now in its 20th year, we will soon know the average age span for both females and males in the wild.

In the first week of a pup’s life, the mum will stay on the beach caring for and bonding with the pup. Gradually, the pup will begin to explore and mum will spend about 15 months teaching them everything they need to know to look after them.

Seal Bay sea lion pups are micro chipped, where possible, allowing important information to be collected by the South Australian Research and Development Institute for the Australian Sea Lion Monitoring Program. This includes monitoring the population of sea lions within the Seal Bay colony, their relationships and mortality. Ideally, fitting pups with a microchip will be the only time in their life that they will come into physical contact with humans.

 

10.  Alpaca 335­-366

The alpaca is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can successfully crossbreed. 

With alpaca birthing, the alpaca’s gestation period averages 11.5 months, but may vary from 11 to 12 months. Any cria born earlier could well need extra help. We tend to bring our heavily pregnant females close to our house for regular observation six weeks before the 11.5 month due date.

Alpacas are generally born between 7am and 3pm and if born later, it is important to make sure the cria is dry before nightfall (and bring it – and mum – into a shelter, if necessary).

The vast majority of crias are born, get up, and feed on their own – without any assistance. However as their mothers do not dry them off at all, we suggest you dry the cria with a clean towel, especially if it is cold or wet (shelter may be necessary – especially early in the year – and you may need to consider fitting a cria coat). If the cria has any blood on it, it should be cleaned off. Check that the cria’s airways (nose and mouth) are clear. We dip the umbilical cord with Iodine (10% Iodine) to prevent infection and repel flies.

It is important not to forget mum – check for any blood on her legs/ tail – and wash off, again so as not too attract flies. Mum should pass the afterbirth in the couple of hours following the birth, and it should be removed and disposed of. The mother’s milk does not tend to flow until the afterbirth has been passed so it is very important to make sure this has occurred.

You can include yours in our comment box. 

Read: Farm Animals: List, Purpose, Image, Types and Facts