Planet Zoo 2 Breeding Calculator

How the breeding calculator works

Each animal's Zoopedia life cycle gives three numbers that set the pace: how long the pregnancy (or incubation) lasts, how many young arrive at once, and how long the mother waits after a birth before she can conceive again. A mother can only have her next young after both have passed, so the shortest time from one birth to the next is the pregnancy plus that wait.

A Lion carries her cubs for 3.6 months, has 1–3 at a time and then waits 32 months, so her births are at least 35.6 months apart. Over five years one lioness can have 2 births, so two lionesses can have up to 12 cubs, or 4 if every litter is a single cub. That is where the calculator starts.

Animals also mate only in their mating season. 27 of the 64 animals in our table breed all year; the rest have a set season such as spring or winter, and every one of them takes close to a year or more between births anyway, so the calculator gives a seasonal mother at most one birth a year. The result is an upper limit: it assumes each mother conceives the moment she can.

What is the interbirth period in Planet Zoo 2?

The interbirth period is the wait after a birth before the mother can conceive again. It is easy to read it as the time between births, but that cannot be right: for 10 animals it is shorter than the pregnancy. A Blacktip Reef Shark, for example, is pregnant for 9 months and then waits only 3 months, so her births are 12 months apart, not 3 months. Frontier's player guide fits this: healthy adults mate in their season as long as they are not still caring for young.

Which Planet Zoo 2 animals breed the fastest

The 15 animals with the most young one mother can have in a year: her largest litter or clutch, as often as her pregnancy and wait allow. Big clutches of eggs put reptiles near the top, and pigs and the African Wild Dog lead the mammals.

The slowest breeders

At the other end, the African Savannah Elephant, Asian Elephant, Sumatran Orangutan and Western Lowland Gorilla have one young at a time and years between births. An African Savannah Elephant is pregnant for 22 months and then waits 108 months, so a cow has a calf only about every 11 years. Plan these herds a long way ahead, and see the Planet Zoo 2 breeding guide for each animal's full life cycle and breeding difficulty.

Why your real numbers will be lower

• Conception is a chance, not a certainty: welfare, Genetics and species Research all change it. Our research checker shows at which levels each animal's two fertility boosts unlock.
• Egg-laying animals need a nest per pair that both can reach.
• A mother still caring for young does not mate, and animals on contraception never do.
• Related animals lose Fertility, and some species become sterile at a set age.
• Newborns do not need extra space, but every young animal that grows up does.

Frontier's guide says juveniles do not change a habitat's space needs, while each adult adds to them. Before a litter grows up, check the bigger group in the Planet Zoo 2 habitat calculator, and its covered space on the Planet Zoo 2 shelter area page.