Longest Gestation Periods in Mammals

About This Dataset

How long different mammals carry their young before birth, measured in days. The African elephant has the longest pregnancy of any land animal at around 670 days - nearly 22 months - far longer than a human's roughly 9 months.

✨ AI Insight

The African elephant (670 days) tops the list, carrying its young for well over twice as long as a human (270 days) and more than ten times longer than a dog. A clear pattern links body size and gestation: the largest animals - elephant, sperm whale (535), white rhinoceros (467) and walrus (456) - occupy the top of the list, as bigger offspring simply take longer to develop. The giraffe (430) and Bactrian camel (390) follow, while familiar domestic animals cluster lower: donkey (365), horse (336) and cow (283) all sit near or just above the human figure. The range shows how mammalian reproduction scales with size, with the biggest species investing almost two years in a single pregnancy.

Source: Wikipedia - List of Mammalian Gestation Durations

Key Findings

Auto-computed highlights from this dataset

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African elephant leads with 670 in All Time.

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Average value in All Time: 420 · median: 410.

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Gap in All Time: African elephant is 2.5× larger than Human.