Gestation periods

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Gestation periods of animals



The Gestation period in a viviparous animal is the length of
its gestation. In humans this is 266 days (38 weeks),
but varies for other animals. Gestation period is
measured from conception to birth. A viviparous animal
is an animal employing vivipary: the embryo develops
inside the body of the mother, from which it gains
nourishment, as opposed to in an egg (ovipary). The
mother then gives live birth. Viviparous offspring
live independently and require an external food supply
from birth. Vivipary is best developed in placental
mammals, but also occurs in many reptiles, some
amphibians, crustaceans (eg. Daphnia), scorpions,
insects (aphids, the tsetse fly, some cockroaches) and
a few fish.

In most birds and reptiles, an egg (Latin: ovum) is the
zygote, resulting from fertilization of the ovum. It
nourishes and protects the embryo. Oviparous animals are animals that
lay eggs, with little or no other development within
the mother. This is the reproductive method of many
fish, amphibians and reptiles, all birds, the
monotremes, and most insects and arachnids.

Ovoviviparous animals develop
within eggs that remain within the mother’s body up
until they hatch or are about to hatch. This strategy
of birth is known as ovoviviparity. It is similar to
vivipary in that the embryo develops within the
mother’s body. Unlike the embryos of viviparous
species, ovoviviparous embryos are nourished by the
egg yolk rather than by the mother’s body. However,
the mother’s body also provides for gas exchange.

Ovoviviparity is employed by many fish (including sharks),
reptiles, and invertebrates. The young of ovoviviparous
amphibians are sometimes born as larvae, and undergo
metamorphosis outside the body of the mother.



Photo:
BBC

Below you’ll find the gestation period of
most animals.

Clicking on the animals name will link you to Wikipedia for more information.

Live-bearing
animals


American Black
Bear
: 7
months

Anteater: 190 days

Arctic Fox: 50 days

Bat: 46 – 70 days

Beaver: 100 – 110 days

Blue whale: 11 – 12 months

Bonobo: 8 months

Brown bear: 255 days

Cat: 63 (58 – 64) days

Cheetah: 90 – 95 days

Chinchilla: 111 (105 – 118) days

Common
Chimpanzee
:
202 – 261 days

Cow: 9 months (275 – 300 days)
>>>
Dog: 63 days

Dolphin: 350 days

Donkey: 275 days (10,5 – 14,4 months)

Elephant
(African)
:
18 – 22 months

Elephant
(Asian)
: 20
– 22 months

Euregian Badger: Female badgers can display delayed
implantation: after mating at any time of the year,
they keep the fertilised eggs in suspended
development until an appropriate time, at which
stage the eggs are implanted and begin developing.
Badgers have a gestation period of 7 – 8 weeks and
give birth to 1 – 5 offspring.

European
polecat
: 6
weaks

Ferret: 42 (41 – 44 days)

Fallow Deer: 234 (225 – 237) days

Fox: 52 – 53 days

Gerbil: 24 – 26 days

Giant Panda: 5 months

Gibbon: 30 weaks

Giraffe: 475 days

Goat: 150 (146 – 157) days

Gorilla: 9 months

Guinea Pig: 2 – 2,5 months

Guppy: 4 – 5 weaks

Hamster: 15 – 17 days

Harbour
porpoise
:
11 months

Hedgehog: 31 – 35 days

Hippopotamus: 240 days

Horse: 335 – 342 days (320-370)

Howler monkey: 6 months

Human: 280 days

Hyena: 110 days

Indian Rhino: 16 months

Jaguar: 110 days

Kangaroo: As with all marsupials, the young
are born at a very early stage of development after
a gestation of 31-36 days. At this stage, only the
forelimbs are somewhat developed, to allow the
newborn to climb to the pouch and attach to a teat.
In comparison, a human embryo at a similar stage of
development would be about 7 weeks old, and
premature babies born at less than 23 weeks are
usually not mature enough to survive. The joey will
usually stay in the pouch for about 9 months or (for
the Western Grey) 180 to 320 days, before starting
to leave the pouch for small periods of time. It is
usually fed by its mother until the age of 18
months.

Lemming: 20 – 22 days

Llama: 331 – 367 days

Lion: 105 – 110 days

Moose: 240 – 270 days

Mole: 4 – 6 weeks

Mouse: 19 – 24 days

Muskrat: 25 – 30 days

Mink: 50 (39 – 59) days

Opossum: 13 days

Orangutan: 275 days

Otter: 61 – 63 days

Pale-throated Three-toed
Sloth
: 170
days

Pig: 115 days

Polar Bear: 240 days

Puma: 91 days

Rabbit: 30 – 31 days

Raccoon:
60 – 73 days

Rat: 18 – 23 days

Red
deer
: 231 (226 –
238) days

Sheep: 147 (137 – 152) days

Spider Monkey: 7 months
Skunk: 2,5 months

Squirrel: 5 – 6 weaks

Tiger: 104 – 112 days

True Seals: 8 – 8,5 months, though there is
an extended gestation: the development of the embryo
starts around 1,5 – 3 months after mating.

Weasel: 34 – 37 days

Whale: 1 year

Wolf:
63 days

Zebra: 12 – 13 months
Egg-laying
animals


Bald Eagle: 45 days

Bearded Dragon: 70 days

Canary: 12 – 14 days

Chicken: 21 days

Common Kestrel: 27 days

Dove: 17 – 18 days

Duck: 23 – 24 days

Emperor Penguin: 67 days

Emu: 50 days

European
Starling
:
12 days

Goose: 30 days

House Sparrow: 12 – 15 days

Komodo Dragon: 8 – 9 months

Nile Crocodile: 96 days

Ostrich: 40 – 44 days

Parakeet: 16 – 31 days

Peafowl: 31 days

Pheasant: 24 days

Platypus: 10 days (the Platypus is
actually a mammal, she does lay eggs but she feeds
her offspring with milk from her mammary glands).

Robin: 12 – 15 days

Snake: 2 – 3 months

Swan: 30 days

Turtle: 100 days



Young turtle





Baby kangaroo in pouch



Baby orangutan with
mother



Baby
crocodile