Breeding, Genetics and Traits

Breeding is how a Planet Zoo 2 zoo pays for itself. Offspring become release groups, conservation credits and replacements for ageing animals. Breeding well (good genes, unrelated pairs, controlled numbers) is what separates a healthy zoo from an overcrowded one.

Reading an animal's traits

Every individual on the market or in your zoo has a trait card:

• Fertility: how easily it conceives. 0% means it will never breed.
• Immunity: resistance to disease. Low immunity animals get sick first.
• Longevity: expected lifespan within the species' range.
• Size and appeal: bigger, more striking animals attract more guests.
• Overall rating: individuals are graded (bronze, silver, gold) based on their traits.

ScreenshotAnimal genetics / traits card

My rule of thumb when buying: nothing below 25% in any trait, and immunity and fertility above everything else. Waiting a couple of market refreshes for a better animal is almost always worth it.

Genetic diversity and related animals

Every pairing has a genetic diversity value. You'll see it when you compare mates or build a release group.

• Siblings and parent/offspring pairs score very low and often can't qualify for release groups.
• Half-related animals came out at around 20% diversity in one hyena group.
• Animals bought from different sources are unrelated. The market shows where each one comes from.
• Some release groups require at least 50% genetic diversity (meerkat mating pairs, owl mating pairs, wolf monogamous pairs, hyena breeding partners).

ScreenshotMate compatibility / genetic diversity check

Preventing inbreeding

The game warns you when an animal is about to inbreed. You have three tools:

1. Contraceptives. Toggle them on a male or on offspring. This is the cleanest fix for a stable family group.
2. Move offspring out. Send maturing young to the trade centre or into a release group.
3. Swap the breeding male. You can't do this while dependent young are present in some species (hyenas, for example). Wait until the cubs grow up.

Note that elderly animals can still breed. An old meerkat matriarch kept producing litters, so check ages when offspring mature.

ScreenshotInbreeding warning & contraceptives

Mating seasons and breeding requirements

• Many species breed in a specific season: rays in summer, golden lion tamarins in autumn and winter, toucans in spring.
• Some need a breeding structure: nests for birds (flamingos and eagles claim them and lay eggs), burrows for meerkats and aardvarks, bedding for antelope.
• A good habitat matters. Unhappy animals breed less.
• Offspring due dates show in the animal panel (for example "second dry season of year 8").

ScreenshotNewborn animals

Overcrowding

Some species breed faster than you can build: meerkats, warthogs, beavers, scorpions, moon jellies, sharks, turtles and butterflies. Signs you've lost control:

• "Habitat is too small" alerts.
• Social or space scores dropping (beavers fell to 69% social/space).
• Fighting from overcrowding (owls).

Fix it by quick releasing, trading, or turning the surplus into release groups. That last option is the best value. See Conservation Credits.

Life stages

Species move from juvenile to adult to elderly. A Komodo dragon spends about 4 years as a juvenile, 5 as an adult and 11 as an elderly animal. Sable antelope mature at about 1.5 years, aardvarks at about 2. Elderly animals eventually die of old age. The game warns you shortly before, so you can plan a replacement and, if you like, a memorial.

Colour variants

Some species have colour variants: individuals with unusual colouration such as a pink-toned clown loach in an orange-and-black shoal. Others, like cownose rays, have no colour morphs at all. See Colour Variants.

A simple breeding programme

1. Buy unrelated founders from different sources, with good fertility and immunity.
2. Research the species for fertility boosts and to unlock release groups.
3. Let the first litters grow up, keeping an eye on the "social group too big" warning.
4. Keep the best young (highest rating and appeal) as future breeders, or swap them into another zoo to avoid inbreeding.
5. Turn the rest into release groups for a wildlife reserve.
6. Replace ageing breeders before they get too old, using the young you kept.

Swapping animals between zoos

If you have two Franchise zoos, you can move young animals between them to mix bloodlines. A female hyena from one zoo and a new male in the other gives you an unrelated pair without buying anything. If you only play one zoo, you can roleplay it: send surplus females to storage and treat it as "lending them to another zoo".

Fast breeders to watch