Reproductive cycles

[Aoi Magi]

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I'll try to explain this in simple terms, so it might not be scientifically accurate.

Let's say all buildings are made with similar units called bricks, arranged differently and in different quantities. So a house with just three rooms would take less time than an entire mansion. Now if the building process is automated, the building times will be quite similar for similar houses or mansions.

In animals, the concept is similar. So depending on the size and complexity of the animals, the time of the gestation varies. For example, Most apes with similar sizes and complexities have similar gestation periods, like chimpanzees with 237 days, gorillas with 257, orangutans with 260 days,and humans with 266 days. Where as dogs and cats have similar periods of around 60 days.

Some species, especially amphibians do show a gestation periods which seem to be partially determined by seasons, but the basic duration is still mostly based on their size and complexity.

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While there are undoubtedly rough relationships between body size and gestation period, the close similarity between the gestation period of the great apes is probably more the result of close evolutionary relationship.

Evolutionary cousins do show similar gestation periods mainly because they are generally similar in size and complexity. But evolutionary cousins with wide size gap do reflect the same in their gestation period difference, for example a rhesus monkey is 164 and a baboon is 187 days.

The primary factors that influence gestation periods are
- Complexity
- Size
- Breeding season
- Babies or litter size