I have an idea about animal migrations. Spawn of animals is quite big so there is enough animals to create “a horde” of deers, birds, wolves, fish, moose etc. Their “horde” should work as a horde of zombies: they gather next to a given forest/ field which depends on animals population. Their migration may be a great hunting opportunity but on the other hand, migrations may be dangerous. Our vehicles may be destroyed by a lot of moose when they don’t see other way to pass our vehicles. And of course wolves and other predators should attack us when we are too close. Hordes should be fast in order to avoid ants, zombies and other monsters.
Actually if you ask the debug menu every mob that is social has a “horde” you just don’t always see it I believe however this only works on wander spawns. I have seen “hordes” of fungaloids and fungal enemies and when you ask the debug menu it will tell you “horde at X,Y,Z moving to target x,y,z consists of 5 X 3 Z and 8 K”(the letters are just variables for like dog cat and wolf as well as location). Hope this helps; however animal hordes don’t really move from what I recall in the game least from what the debug tells me they tend to stay in one place Most of the time only time I’ve seen them move is to follow your scent and then they set target to you.