Animal Gestation and Incubation Periods

Gestation is the time between conception and birth in animals that bear live young. For egg-laying animals the equivalent figure is the incubation or egg development period, from laying to hatching. In mammals, gestation rises with body size, from about three weeks in mice to nearly two years in elephants; marsupials are the exception, with very short pregnancies followed by a long period in the pouch.

Animals With the Longest Gestation Period

214 animals, A–Z. Tap a column heading to sort.

Animal	Class	Gestation / incubation	Notes
African Buffalo	Mammals	about 340 days (11 months)	Gestation
African Elephant	Mammals	about 22 months (around 650 days)	Gestation
African Grey Parrot	Birds	28–30 days	Incubation
African Spurred Tortoise	Reptiles	90–120 days in incubators; longer in the wild	Incubation
African Wild Dog	Mammals	about 70 days	Gestation
Alpaca	Mammals	about 345 days (11.5 months)	Gestation
American Alligator	Reptiles	about 65 days	Incubation
American Bison	Mammals	about 9.5 months (270–285 days)	Gestation
American Black Bear	Mammals	about 220 days (7 months), including delayed implantation	Gestation
American Bullfrog	Amphibians	3–5 days to hatch	Egg development
American Crow	Birds	16–18 days	Incubation
American Lobster	Invertebrates	9–12 months carried under the female's tail	Egg development
American Robin	Birds	12–14 days	Incubation
American Toad	Amphibians	3–12 days to hatch	Egg development
Andean Condor	Birds	54–58 days	Incubation
Arctic Fox	Mammals	about 52 days	Gestation
Asian Elephant	Mammals	18–22 months (about 650 days)	Gestation
Asian Giant Hornet	Invertebrates	—
Atlantic Bluefin Tuna	Fish	about 2 days	Egg development
Atlantic Puffin	Birds	39–45 days	Incubation
Atlantic Salmon	Fish	roughly 70–160 days, depending on water temperature	Egg development
Axolotl	Amphibians	10–14 days to hatch	Egg development
Bactrian Camel	Mammals	about 13 months	Gestation
Bald Eagle	Birds	about 35 days	Incubation
Ball Python	Reptiles	55–60 days	Incubation
Barn Owl	Birds	29–34 days	Incubation
Beluga Sturgeon	Fish	about 6–10 days	Egg development
Beluga Whale	Mammals	12–15 months (usually about 14)	Gestation
Betta Fish	Fish	24–48 hours	Egg development
Black Garden Ant	Invertebrates	—
Black Mamba	Reptiles	60–90 days	Incubation
Black Rhinoceros	Mammals	15–16 months (450–480 days)	Gestation
Blue Whale	Mammals	10–12 months	Gestation
Blue Wildebeest	Mammals	about 8–8.5 months (240–255 days)	Gestation
Boa Constrictor	Reptiles	100–120 days	Gestation
Bobcat	Mammals	60–70 days	Gestation
Bonobo	Mammals	about 8 months (240 days)	Gestation
Bornean Orangutan	Mammals	about 8.5 months (245–265 days)	Gestation
Bottlenose Dolphin	Mammals	about 12 months	Gestation
Bowhead Whale	Mammals	13–14 months	Gestation
Brown Rat	Mammals	21–24 days	Gestation
Brown-Throated Sloth	Mammals	5–7 months (150–210 days)	Gestation
Budgerigar	Birds	18–21 days	Incubation
Buff-Tailed Bumblebee	Invertebrates	4–6 days	Egg development
Bull Shark	Fish	10–11 months	Gestation
Burmese Python	Reptiles	60–70 days	Incubation
California Sea Lion	Mammals	about 11 months, including delayed implantation	Gestation
Canada Goose	Birds	24–28 days	Incubation
Cane Toad	Amphibians	1–3 days to hatch	Egg development
Capybara	Mammals	130–150 days	Gestation
Cat	Mammals	63–65 days	Gestation
Central Bearded Dragon	Reptiles	55–75 days	Incubation
Cheetah	Mammals	about 93 days	Gestation
Chicken	Birds	21 days	Incubation
Chimpanzee	Mammals	about 230 days (7.5–8 months)	Gestation
Chinese Giant Salamander	Amphibians	50–60 days to hatch	Egg development
Cockatiel	Birds	18–21 days	Incubation
Common Earthworm	Invertebrates	about 3–4 months at 15–20 °C; longer in cold soil	Egg development
Common Octopus	Invertebrates	about 1–4 months, depending on water temperature	Egg development
Common Ostrich	Birds	about 42 days	Incubation
Common Raven	Birds	20–25 days	Incubation
Common Starfish	Invertebrates	—
Common Swift	Birds	19–21 days	Incubation
Common Vampire Bat	Mammals	about 7 months (205–215 days)	Gestation
Common Warthog	Mammals	5–6 months (about 170 days)	Gestation
Common Wasp	Invertebrates	5–8 days	Egg development
Common Wombat	Mammals	20–30 days	Gestation
Cougar	Mammals	about 91 days	Gestation
Cow	Mammals	about 283 days (9 months)	Gestation
Coyote	Mammals	60–63 days	Gestation
Dog	Mammals	about 63 days	Gestation
Donkey	Mammals	about 12 months (11–14 months)	Gestation
Dromedary Camel	Mammals	about 13 months (12–15 months)	Gestation
Eastern Gray Squirrel	Mammals	about 44 days	Gestation
Eastern Newt	Amphibians	3–5 weeks to hatch	Egg development
Electric Eel	Fish	—
Elk	Mammals	240–262 days (about 8.5 months)	Gestation
Emperor Dragonfly	Invertebrates	about 3–4 weeks	Egg development
Emperor Penguin	Birds	about 65 days	Incubation
Emperor Scorpion	Invertebrates	about 7–9 months	Gestation
Emu	Birds	about 56 days (8 weeks)	Incubation
European Hare	Mammals	41–42 days	Gestation
European Hedgehog	Mammals	31–35 days	Gestation
European Mantis	Invertebrates	about 7–9 months (eggs overwinter)	Egg development
Fennec Fox	Mammals	50–52 days	Gestation
Fire Salamander	Amphibians	—
Galápagos Tortoise	Reptiles	about 4–8 months (120–240 days)	Incubation
Garden Snail	Invertebrates	2–4 weeks	Egg development
Giant Anteater	Mammals	170–190 days	Gestation
Giant Clam	Invertebrates	about 12 hours (0.5 days) from fertilization to hatching	Egg development
Giant Manta Ray	Fish	12–13 months	Gestation
Giant Panda	Mammals	95–160 days (about 135 on average), including delayed implantation	Gestation
Giant Squid	Invertebrates	—
Gila Monster	Reptiles	about 4 months in incubators; around 10 months in wild nests	Incubation
Giraffe	Mammals	about 15 months (420–460 days)	Gestation
Goat	Mammals	about 150 days (5 months)	Gestation
Golden Eagle	Birds	41–45 days	Incubation
Golden Poison Frog	Amphibians	about 10–14 days to hatch	Egg development
Goldfish	Fish	2–7 days	Egg development
Goliath Birdeater	Invertebrates	6–8 weeks	Egg development
Goliath Frog	Amphibians	—
Gray Wolf	Mammals	about 63 days	Gestation
Great Hammerhead Shark	Fish	about 11 months	Gestation
Great Horned Owl	Birds	30–37 days	Incubation
Great White Shark	Fish	an estimated 11–12 months	Gestation
Greater Flamingo	Birds	27–31 days	Incubation
Green Anaconda	Reptiles	6–7 months	Gestation
Green Iguana	Reptiles	90–120 days	Incubation
Green Sea Turtle	Reptiles	about 60 days	Incubation
Greenland Shark	Fish	—
Grizzly Bear	Mammals	180–250 days (6–8 months), including delayed implantation	Gestation
Guinea Pig	Mammals	59–72 days	Gestation
Guppy	Fish	21–30 days	Gestation
Hamster	Mammals	16–18 days	Gestation
Harbor Seal	Mammals	9–11 months, including delayed implantation	Gestation
Hippopotamus	Mammals	about 8 months (227–240 days)	Gestation
Honey Badger	Mammals	50–70 days	Gestation
Horse	Mammals	about 340 days (11 months)	Gestation
House Mouse	Mammals	19–21 days	Gestation
Housefly	Invertebrates	8–24 hours	Egg development
Humpback Whale	Mammals	about 11.5 months	Gestation
Immortal Jellyfish	Invertebrates	—
Indian Cobra	Reptiles	48–69 days	Incubation
Indian Peafowl	Birds	28–30 days	Incubation
Indo-Pacific Sailfish	Fish	about 36 hours	Egg development
Jaguar	Mammals	about 100 days	Gestation
Japanese Macaque	Mammals	about 173 days (5.5–6 months)	Gestation
Japanese Spider Crab	Invertebrates	—
King Cobra	Reptiles	60–90 days	Incubation
Koala	Mammals	33–36 days	Gestation
Koi	Fish	3–7 days	Egg development
Komodo Dragon	Reptiles	7–8 months	Incubation
Largemouth Bass	Fish	2–5 days	Egg development
Leatherback Sea Turtle	Reptiles	60–70 days	Incubation
Leopard	Mammals	90–105 days	Gestation
Leopard Gecko	Reptiles	35–90 days, depending on temperature	Incubation
Lined Seahorse	Fish	2–3 weeks (carried by the male)	Gestation
Lion	Mammals	about 110 days	Gestation
Llama	Mammals	about 350 days (11.5 months)	Gestation
Luna Moth	Invertebrates	8–13 days	Egg development
Mallard	Birds	26–30 days	Incubation
Mandrill	Mammals	about 175 days (6 months)	Gestation
Meerkat	Mammals	70–77 days	Gestation
Monarch Butterfly	Invertebrates	3–5 days	Egg development
Moon Jellyfish	Invertebrates	—
Moose	Mammals	about 230 days (8 months)	Gestation
Mute Swan	Birds	35–41 days	Incubation
Naked Mole-Rat	Mammals	about 70 days	Gestation
Narwhal	Mammals	14–15 months	Gestation
Nile Crocodile	Reptiles	80–90 days	Incubation
Nine-Banded Armadillo	Mammals	about 120 days, after a 3–4 month implantation delay	Gestation
North American Beaver	Mammals	105–128 days	Gestation
North Island Brown Kiwi	Birds	75–90 days	Incubation
Northern Cardinal	Birds	11–13 days	Incubation
Ocean Quahog	Invertebrates	—
Ocean Sunfish	Fish	—
Ocellaris Clownfish	Fish	6–8 days	Egg development
Okapi	Mammals	440–450 days (about 14.5 months)	Gestation
Orca	Mammals	15–18 months	Gestation
Peregrine Falcon	Birds	29–33 days	Incubation
Pig	Mammals	about 114 days	Gestation
Plains Zebra	Mammals	12–13 months (360–396 days)	Gestation
Platypus	Mammals	about 10 days	Incubation
Polar Bear	Mammals	195–265 days (about 8 months), including delayed implantation	Gestation
Pronghorn	Mammals	about 250 days (8 months)	Gestation
Rabbit	Mammals	28–31 days	Gestation
Raccoon	Mammals	63–65 days	Gestation
Rainbow Trout	Fish	about 4–7 weeks	Egg development
Red Deer	Mammals	about 235 days (33–34 weeks)	Gestation
Red Fox	Mammals	about 52 days	Gestation
Red Kangaroo	Mammals	about 33 days	Gestation
Red Panda	Mammals	112–158 days (about 135 on average)	Gestation
Red-Bellied Piranha	Fish	2–3 days	Egg development
Red-Eared Slider	Reptiles	60–90 days	Incubation
Red-Eyed Tree Frog	Amphibians	6–8 days to hatch	Egg development
Red-Tailed Hawk	Birds	28–35 days	Incubation
Reindeer	Mammals	about 228 days (7.5 months)	Gestation
Reticulated Python	Reptiles	80–90 days	Incubation
Ring-Tailed Lemur	Mammals	about 135 days (4.5 months)	Gestation
Rock Pigeon	Birds	17–19 days	Incubation
Ruby-Throated Hummingbird	Birds	12–14 days	Incubation
Saltwater Crocodile	Reptiles	80–90 days	Incubation
Scarlet Macaw	Birds	24–28 days	Incubation
Sea Otter	Mammals	4–12 months (about 6 on average), including delayed implantation	Gestation
Seven-Spot Ladybug	Invertebrates	4–10 days, depending on temperature	Egg development
Sheep	Mammals	about 147 days (5 months)	Gestation
Snow Leopard	Mammals	90–105 days	Gestation
Snowy Owl	Birds	about 32 days	Incubation
Southern Black Widow	Invertebrates	20–30 days	Egg development
Sperm Whale	Mammals	14–16 months	Gestation
Spotted Hyena	Mammals	about 110 days	Gestation
Springbok	Mammals	5–6 months (about 168 days)	Gestation
Striped Skunk	Mammals	59–77 days	Gestation
Swordfish	Fish	about 2.5 days	Egg development
Tasmanian Devil	Mammals	about 21 days	Gestation
Thomson's Gazelle	Mammals	5–6 months (160–180 days)	Gestation
Tiger	Mammals	about 103 days	Gestation
Tiger Shark	Fish	13–16 months	Gestation
Toco Toucan	Birds	17–18 days	Incubation
Tuatara	Reptiles	12–15 months	Incubation
Veiled Chameleon	Reptiles	about 5–9 months, depending on temperature	Incubation
Walrus	Mammals	15–16 months, including delayed implantation	Gestation
Wandering Albatross	Birds	about 78 days (11 weeks)	Incubation
West Indian Manatee	Mammals	12–14 months	Gestation
Western Diamondback Rattlesnake	Reptiles	6–7 months	Gestation
Western Gorilla	Mammals	about 8.5 months (257 days)	Gestation
Western Honey Bee	Invertebrates	3 days	Egg development
Whale Shark	Fish	—
White Rhinoceros	Mammals	about 16 months (roughly 490 days)	Gestation
White-Tailed Deer	Mammals	about 200 days (6.5 months)	Gestation
Wild Boar	Mammals	about 115 days (up to 140)	Gestation
Wild Turkey	Birds	about 28 days	Incubation
Wolverine	Mammals	30–50 days of active pregnancy	Gestation
Yellow Fever Mosquito	Invertebrates	2–7 days, then eggs hatch when flooded	Egg development

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