Pet Rodent Gestation Chart

Gestation by species, shortest to longest

These are typical figures, and a single animal can run a little outside them. The short-gestation rodents, like the hamster and mouse, are born tiny, blind and hairless. The longer ones, the guinea pig and chinchilla, are born furred with their eyes open and need less time on the mother.

Why the range is so wide

A chinchilla's 111 days is nearly seven times a hamster's 16, even though both are small pets. The pattern is simple: the more developed the young are at birth, the longer the pregnancy. A newborn hamster is barely formed, so it is born fast and finishes growing in the nest. A newborn guinea pig can walk and eat almost at once, which it pays for with a long pregnancy.

Calculators and the bigger chart

For a due date, use the guinea pig gestation calculator or the rabbit gestation calculator. Farm animals and wild species, from cows to elephants, are in the animal gestation periods chart.

Frequently asked questions

Sources

• Merck Veterinary Manual: Biological data of pet rodents
• Merck Veterinary Manual: Physiological data for guinea pigs

Calculators for this

Last updated November 12, 2026. Dates are averages with a normal window. How we check our data. Found an error? Tell us.