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Biology Summaries
Pregnancy Length

Gestation Periods - Summary Chart

Here is a pregnancy period comparison chart of human babys, selected pets and other mammals.



The length of a human pregnancy is usually referred to as "9 months" for a baby, which is not completely accurate. It's eight days less.

The length of time in the womb for humans and other mammals varies considerably, based mostly upon size. Note that the length of a mammal's llfe expectancy is also closely related to its physical size.


Length of Human Pregnancy vs.
Some Pets and Other Animals

-

Mammal
Species
# of
Days

Life
Expect.
Years

   Notes


Group

1

Opossom

12

-

 small size
 rapid heart rate
 short life

Hamster

16

-

 

 -

-

Mouse/ Rat

21

-

Rabbit

31

-

Skunk

31

-

 (gap)

Group

2

Squirrel

44

-

 (years)

Eagle, Golden

44

-

 -

Bobcat

60

-

 -

Dog

61

-

 50-70 days- species dependent

Cat

63

-

 58 - 65 days

Scorpion

90 - 540

-

 highly species dependent

Lion

108

-

 -

Pig

114

-

 -

Goat

145

-

 -

Sheep

150

-

 -

  (gap)

Group

3

Bear, Grizzly

220

-

  (tens of years)

Human baby

266
76

 (9 months = 274 days)

Cow

284

-

 -

 -

 (gap)

 -

 -

Horse

336
25

 -

Sea Lion

360

-

 -

Wha|e

360
80

 -

Donkey

374

-

 

  (gap)

Group

4

Camel

400
40

 large size
 slow heart rate
 long life

Giraffe

425
25

Rhino, Grey

480

-

 

  (gap)

 -

Rhino, Black

540

-

Elephant, Asia

610

-

Elephant, Afr.

660

-

 
Average human baby pregnancy time vs. other mammals.
The larger the animal, the longer the gestation period, in general.
In general, the larger the animal, the longer the life.

50

100

50

50

200 - 450

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This Vaughns Summaries Gestation Period Summary
was last updated on 2012-05-04.