The gestation period is the time a baby needs to grow inside its mother before it is ready to be born. This happens in almost all mammals. Some other animals do it too, but those animals carry babies that are already fully formed, rather than still growing.
Humans carry their babies for about 9 months. Most animals need less time than that, but a few take much longer. As a rough rule, bigger animals tend to have longer pregnancies. But that rule does not always hold. Blue whales are the largest animals that have ever lived on Earth, yet they are not pregnant the longest. Smaller animals like tapirs, camels, and elephants actually carry their young for more days. Here's a look at the gestation periods of many different animals.
🧮 How long, compared to you?
Pick any animal and see how its pregnancy stacks up against a human's nine months.
The Full Gestation Period Chart
Here is the complete list, grouped from the longest pregnancies down to the very shortest. Every figure is the number of days the baby develops before it is born.
📊 Sorted longest → shortest. Tap a column heading to re-sort the whole chart.
| Animal | Gestation (days) | In human terms |
|---|---|---|
| 🐘 The Marathon MakersAbout 400-750 days | ||
| African ElephantLoxodonta africana | 600-750 | ~22.2 months |
| Asian ElephantElephas maximus | 550-650 | ~19.7 months |
| Sperm WhalePhyseter macrocephalus | 480-590 | ~17.6 months |
| OrcaOrcinus orca | 450-550 | ~16.4 months |
| WalrusPhoca rosmarus | 450-500 | ~15.6 months |
| GiraffeGiraffa camelopardalis | 420-450 | ~14.3 months |
| Black RhinocerosDiceros bicornis | 400-450 | ~14.0 months |
| Brazilian TapirTapirus terrestris | 380-400 | ~12.8 months |
| Dromedary CamelCamelus dromedarius | 360-420 | ~12.8 months |
| Plains ZebraEquus quagga | 360-400 | ~12.5 months |
| Blue WhaleBalaenoptera musculus | 300-400 | ~11.5 months |
| 🦛 The Long HaulersAbout 250-400 days | ||
| Bottlenose DolphinTursiops truncatus | 350-370 | ~11.8 months |
| California Sea LionZalophus californianus | 350-375 | ~11.9 months |
| DonkeyEquus africanus asinus | 340-380 | ~11.8 months |
| HorseEquus ferus caballus | 330-360 | ~11.3 months |
| African BuffaloSyncerus caffer | 330-350 | ~11.2 months |
| Harbour PorpoisePhocoena phocoena | 300-350 | ~10.7 months |
| Long-tailed WeaselMustela frenata | 280-310 | ~9.7 months |
| CowBos primigenius | 280-290 | ~9.4 months |
| HumansHomo sapiens sapiens | 260-290 | ~9.0 months |
| GorillaGorilla gorilla gorilla | 250-260 | ~8.4 months |
| OrangutanPongo borneo | 245-275 | ~8.6 months |
| Polar BearUrsus maritimus | 240-250 | ~8.1 months |
| MooseAlces alces | 240-250 | ~8.1 months |
| Sambar DeerRusa unicolor | 230-250 | ~7.9 months |
| ChimpanzeePan troglodytes | 230-250 | ~7.9 months |
| HippopotamusHippopotamus amphibius | 225-250 | ~7.8 months |
| ReindeerRangifer tarandus | 210-250 | ~7.6 months |
| 🐐 The Middle of the PackAbout 150-250 days | ||
| Black BearUrsus americanus | 220-230 | ~7.4 months |
| American BisonBison bison | 215-220 | ~7.2 months |
| Brown BearUrsus arctos | 200-220 | ~6.9 months |
| Sloth BearMelursus ursinus | 200-220 | ~6.9 months |
| Brown-throated SlothBradypus variegatus | 200-220 | ~6.9 months |
| Gray LangurSimia entellus | 180-200 | ~6.2 months |
| Giant AnteaterMyrmecophaga tridactyla | 180-200 | ~6.2 months |
| White-handed GibbonHylobates lar | 175-190 | ~6.0 months |
| Lion-tailed MacaqueMacaca silenus | 170-190 | ~5.9 months |
| BaboonPapio hamadryas | 170-190 | ~5.9 months |
| MandrillMandrillus sphinx | 165-180 | ~5.7 months |
| Proboscis MonkeyNasalis larvatus | 160-205 | ~6.0 months |
| Rhesus MacaqueMacaca mulatta | 150-175 | ~5.3 months |
| Domestic GoatCapra aegagrus hircus | 145-155 | ~4.9 months |
| SheepOvis aries | 145-155 | ~4.9 months |
| Tree PangolinManis tricuspis | 145-150 | ~4.9 months |
| Giant PandaAiluropoda Melanoleuca | 95-160 | ~4.2 months |
| 🐅 The Quick GrowersAbout 90-150 days | ||
| Yellow MongooseCynictis penicillata | 120-130 | ~4.1 months |
| BeaverCastor canadensis | 115-130 | ~4.0 months |
| Domestic PigSus domesticus | 110-115 | ~3.7 months |
| ChinchillaChinchilla chinchilla | 105-115 | ~3.6 months |
| PorcupineErethizon dorsatum | 100-120 | ~3.6 months |
| LionPanthera leo | 100-115 | ~3.5 months |
| Bengal TigerPanthera tigris tigris | 100-110 | ~3.5 months |
| Striped HyenaHyaena hyaena | 90-110 | ~3.3 months |
| Siberian TigerPanthera tigris altaica | 90-100 | ~3.1 months |
| LeopardPanthera pardus | 90-100 | ~3.1 months |
| CheetahAcinonyx jubatus | 90-100 | ~3.1 months |
| 🐹 The Speedy SprintersUnder 90 days | ||
| MeerkatSuricata suricatta | 75-80 | ~2.5 months |
| Egyptian MongooseHerpestes ichneumon | 75-80 | ~2.5 months |
| African Wild DogLycaon pictus | 65-75 | ~2.3 months |
| Eurasian OtterLutra lutra | 60-80 | ~2.3 months |
| RaccoonProcyon lotor | 60-70 | ~2.1 months |
| North American River OtterLontra canadensis | 60-80 | ~2.3 months |
| Gray WolfCanis lupus lupus | 60-70 | ~2.1 months |
| SkunkMephitis mephitis | 60-65 | ~2.1 months |
| CatFelis catus | 55-65 | ~2.0 months |
| DogCanis lupus familiaris | 55-65 | ~2.0 months |
| Guinea PigCavia porcellus | 55-75 | ~2.1 months |
| Red FoxVulpes vulpes | 50-60 | ~8 weeks |
| KangarooMacropus rufus | 30-40 | ~5 weeks |
| Gray SquirrelSciurus carolinensis | 30-40 | ~5 weeks |
| Prairie DogCynomys genus | 30-40 | ~5 weeks |
| ChipmunkTamias genus | 30-35 | ~5 weeks |
| Domestic RabbitOryctolagus cuniculus | 25-35 | ~4 weeks |
| MuskratOndatra zibethicus | 25-30 | ~4 weeks |
| WombatVombatus ursinus | 25-30 | ~4 weeks |
| Domesticated / Mongolian GerbilMeriones unguiculatus | 20-25 | ~3 weeks |
| Black RatRattus rattus | 20-23 | ~3 weeks |
| MouseMus musculus | 20-22 | ~3 weeks |
| Golden HamsterMesocricetus auratus | 15-20 | ~2 weeks |
Record-Holders Up Close
A few of these animals tell the chart's most surprising stories, here they are with their young.
African Elephant Loxodonta africana
600-750 days
The all-time champion. An elephant calf grows for up to two years before it is born, longer than any other land animal on the chart.
Lion Panthera leo
100-115 days
A big cat surprise: despite their size, lionesses carry their cubs for only about three and a half months, right alongside tigers and leopards.
Sambar Deer Rusa unicolor
230-250 days
Deer sit in the middle of the pack. A fawn develops for roughly eight months and can stand and walk almost as soon as it is born.
Black Rhinoceros Diceros bicornis
400-450 days
One of the long-haulers. A rhino mother carries her single calf for around fifteen months before it arrives.
Dromedary Camel Camelus dromedarius
360-420 days
Proof that size is not everything, a camel actually outlasts the mighty blue whale, carrying its calf for about thirteen months.
Take the Gestation Detective Quiz!
5 quick questions. Find out how much of a baby-animal expert you really are.
What the Chart Shows
Animals that are related to each other usually have similar gestation periods. Look at the chart and you can see the pattern. Apes (including humans), monkeys, big cats, and rodents each cluster together, animals in the same group tend to take roughly the same amount of time.
The platypus and 4 species of echidnas do not give birth to live young, despite being a mammal. They are the only mammals who lay eggs.
Frequently Asked Questions
Which animal has the longest gestation period?
The African elephant has the longest gestation period of the animals on this chart, at about 600 to 750 days, close to two years.
Does a bigger animal always have a longer pregnancy?
No. As a rough rule gestation depends on size, but it is not always true. The blue whale, the largest animal ever, is outdone by smaller animals such as tapirs, camels, and elephants.
Which mammal has the shortest gestation period?
Opossums have the shortest gestation periods of all mammals, some opossum species are born in less than 10 days.
How long is a human gestation period?
Humans carry their babies for about nine months, roughly 260 to 290 days.
Fun fact for today!An elephant is pregnant for almost two whole years, the longest of any animal on this chart!