The elephant has the longest gestation period at 22 months. This is longer than that of the blue whale, which is one year. Some species of dolphins have a gestation period of 17 months and sperm whales carry their young for up to 19 months. Rhinos have a gestation period of about 450 days. Owing to such long gestation, the population of these species are not quickly replenished.
Longest gestation periods in the animal kingdom
