For most species, the amount a fetus grows before birth determines the length of the gestation period. Smaller species normally have a shorter gestation period than larger animals. For example, a cat's gestation normally takes 58–65 days while an elephant's takes nearly 2 years (21 months). However, growth does not necessarily determine the length of gestation for all species, especially for those with a breeding season. Species that use a breeding season usually give birth during a specific time of year when food is available.
For most species, the amount a fetus grows before birth determines the leng,th of the gestation period. Smaller species normally have a shorter gestation period than larger animals. For example a cat's gestation normally takes 5,8–65 days while an elephant's takes nearly 2 years (21 months) However, growth does not necessarily determine the length of gestation for all species especially for those with a breeding season. Species that use a breeding se.ason usually give birth during a specific time of year when food is available.