Animals With the Longest Gestation Period
Number one is the asian elephant at 18–22 months (about 650 days) (Gestation), followed by the african elephant at about 22 months (around 650 days) and the orca at 15–18 months.
| # | Animal | Gestation | Notes |
|---|---|---|---|
| 1 | Asian Elephant Mammal |
18–22 months (about 650 days) | Gestation |
| 2 | African Elephant Mammal |
about 22 months (around 650 days) | Gestation |
| 3 | Orca Mammal |
15–18 months | Gestation |
| 4 | White Rhinoceros Mammal |
about 16 months (roughly 490 days) | Gestation |
| 5 | Sperm Whale Mammal |
14–16 months | Gestation |
| 6 | Walrus Mammal |
15–16 months, including delayed implantation | Gestation |
| 7 | Black Rhinoceros Mammal |
15–16 months (450–480 days) | Gestation |
| 8 | Tiger Shark Fish |
13–16 months | Gestation |
| 9 | Narwhal Mammal |
14–15 months | Gestation |
| 10 | Beluga Whale Mammal |
12–15 months (usually about 14) | Gestation |
| 11 | Giraffe Mammal |
about 15 months (420–460 days) | Gestation |
| 12 | Okapi Mammal |
440–450 days (about 14.5 months) | Gestation |
| 13 | Dromedary Camel Mammal |
about 13 months (12–15 months) | Gestation |
| 14 | Bowhead Whale Mammal |
13–14 months | Gestation |
| 15 | West Indian Manatee Mammal |
12–14 months | Gestation |
| 16 | Bactrian Camel Mammal |
about 13 months | Gestation |
| 17 | Donkey Mammal |
about 12 months (11–14 months) | Gestation |
| 18 | Plains Zebra Mammal |
12–13 months (360–396 days) | Gestation |
| 19 | Giant Manta Ray Fish |
12–13 months | Gestation |
| 20 | Bottlenose Dolphin Mammal |
about 12 months | Gestation |
| 21 | Horse Mammal |
about 340 days (11 months) | Gestation |
| 22 | Blue Whale Mammal |
10–12 months | Gestation |
| 23 | Great White Shark Fish |
an estimated 11–12 months | Gestation |
| 24 | Humpback Whale Mammal |
about 11.5 months | Gestation |
| 25 | Sea Otter Mammal |
4–12 months (about 6 on average), including delayed implantation | Gestation |
About this ranking
Elephants have the longest pregnancy of any mammal, close to two years. Long gestation goes with large body size and with giving birth to a single, well-developed calf that can stand and follow the herd within hours. A few live-bearing sharks are thought to carry their young even longer, although their pregnancies are much harder to observe.
How it is ranked: Live-bearing animals ranked by the upper end of the typical gestation period in days. Egg incubation times are not included. The list covers the 214 animals in the AnimalStats database, not every species on Earth.
The top five in detail
1. Asian Elephant — 18–22 months (about 650 days)
An Asian elephant is pregnant for 18–22 months, around 650 days, among the longest pregnancies of any mammal. A cow has one calf at a time, usually every four to five years. Calves nurse for two to three years and are looked after by the whole herd.
2. African Elephant — about 22 months (around 650 days)
An African elephant is pregnant for about 22 months, roughly 650 days, the longest gestation of any land mammal. A cow normally has a single calf every four to five years. The calf can stand within an hour and is cared for by the whole family, not just its mother.
3. Orca — 15–18 months
An orca pregnancy lasts 15–18 months, the longest known of any dolphin or whale. A single calf, about 2.4 m long, is born tail first and nurses for one to two years. Females give birth roughly every five years and stop reproducing at around 40, then live on for decades.
4. White Rhinoceros — about 16 months (roughly 490 days)
A white rhino is pregnant for about 16 months, roughly 490 days, one of the longest pregnancies of any land mammal. The single calf weighs 40–65 kg at birth and stays with its mother for two to three years, until the next calf arrives. Females breed only every two and a half to three years.
5. Sperm Whale — 14–16 months
A sperm whale is pregnant for 14–16 months, one of the longest pregnancies of any mammal. The single calf is about 4 m long and weighs about a tonne at birth. It may nurse for several years, and females give birth only once every four to six years or more.