Passive animals have little to no interaction with Hominids. Some can be caught and eaten such as the Bass or Giant African Snail, while others are purely decorations in the game such as the various bird species, as well as the numerous toads, insects, and bats.
Wild Animals are common in the Savanna region. Their behavior is mostly passive. They will run from a hominid if approached, but will attack the hominid then flee if they are cornered or get too close to the animal. There is no intimidation check in order to cause a Wild Animal run away, which is why there is no Evolution Feat for intimidating Wild Animals. Both Wild Animals have relatively low health and it is possible kill them with one successful counterattack with a Sharpened Stick.
Irascible Threats are found most commonly in the Jungle and Savanna regions. Their behavior is mostly passive, but if a hominid approaches them, they will attempt an intimidation. You can try to intimidate the adversary but if you do not succeed the threat will attack and then flee. The intimidation check requirement rises as more of the same species animal are in the same group. Most Irascible Threats have relatively high health, with the Miocene African Otter having the lowest health.
Crawling Threats can be found everywhere throughout the accessible world. Their behavior is similar to that of Irascible Threats in that they will attempt to intimidate your hominid before attacking and will not back down once approached. Crawling Threats are relatively easy to intimidate into fleeing, but if you do not have a high enough intimidation score, the animal will attack if it is close enough.
Predators can be found in all regions of the accessible world. They will actively pursue a hominid if they spot them, and attack them once they achieve their preferred attack position. Each type of predator has different attack strategies against hominids. Most Predators have a high intimidation check in order to successfully cause them to flee. Different types of Predators have slightly different intimidation tactics to use against you. For example, Hyenas and Black-Backed Jackals tend to surround a hominid as they tend to travel in groups, and while they are surrounding them they lower your dopamine levels. In contrast to all varieties of Machairodus, which attempt to ambush you by approaching from behind or through dense vegetation, but if you spot them they will charge outright.
Flying Predators are classified as "Predators" in the game, but their behavior patterns are completely different from the other predators. Flying Predators have a designated "zone" in which their attacks occur. If you stay still for too long, the call from the aerial predator will be heard in the distance, and if you still do not move from that spot, the bird will attack by swooping down a few moments later.