There are two ways an animal can become unwell in Planet Zoo.
Infection
The primary sources of infection are:
- Contagion from other sick animals in the same habitat.
- Dirty habitats caused by a buildup of dung, rotting food, corpses, guest food and dirty water.
- Feeding from the ground.
Quarantining newly adopted animals will help to block new diseases entering the zoo, as it gives vets a chance to detect and treat diseases before they are introduced into the wider population.
To help reduce the chances of infection, keepers can be deployed to clean habitats and water treatment facilities can be used to keep bodies of water clear. Keepers and vets may detect an illness either whilst it is incubating or in an infectious state when they examine a habitat.
You can choose to box animals and have them sent to quarantine to reduce the likelihood of an infection spreading. Animals are transferred to quarantine by caretakers and will be moved automatically into a vet surgery by a vet when one becomes available.
There is a chance that animals will recover on their own, but the likelihood of this happening depends on their welfare and immunity. A vet will always heal an animal faster and more reliably. Animals that have caught a disease will become immune to future infections by the same one.
Physical injury
Animals can become injured either through fights amongst themselves or attacks from their predators.
Fighting within a species normally occurs due to one of three issues:
- Dominance fights where an animal is attempting to take alpha status from another.
- Fighting due to social imbalances in the group makeup.
- Stress fighting due to overcrowding.
Often fighting can be avoided through good animal husbandry and predation can be avoided by separating unsuitable animals.
Treatment for injuries follows the same process as for disease, but animals with light injuries may also heal themselves over time depending on the animal's welfare and immunity.
Injuries that heal will leave the animal with a permanent scar.