Once again asking for every type of animal to have a "subtype" with a different behavior/biome to make the environment feel more alive. Subtype of each as follows:
Crab: Coconut crab found in palm trees. They would knock down coconuts that pachy could eat, whereas ptera hunting them would need to peck them out of the tree.
Boar: Domestic pig, fodder for humans in the future. Risk/reward of poaching them from said humans, as they'd be in groups by human settlements vs scattered around.
Chicken: Rooster that sticks around hens, periodically crows, actually attempts to fight back against small threats instead of running.
Deer: Bucks/stags that herd alongside one to three does. Will attempt to fight back by goring and kicking small predators.
Turtles: Snapping turtles in the river shallows. AI that will actually prove a difficult hunt for young deino, with bites causing bleed, a tanky shell, etc. Also gives ptera another turtle option that provides a challenge to take down.
Goat: I honest to god have never seen a goat in-game, lmao, but having mountain goats that are specifically found around high altitudes would make those areas actually worth going to.
Elite fish: Some sort of large, aggressive fish (freshwater sharks?), bigger than the existing elite fish that spawn. Again another AI that would actually fight back against younger deino, while also providing a meal worth something to adults so they don't have to drain the entire river of fish to feed themselves.
Schooling fish: Tropical fish in the ocean to give ptera more reason to stick around the coast. I never really see them there as-is, especially nesting.
A lot of these suggestions incorporate the AI roaming in small "herds" vs being sprinkled around haphazardly; even something as simple as having them spawn in groups (like RDR2 for example, spawning animal AI in groups of 3 or more) would breathe a bit more life into the environment and feel more... Natural + encourage pack hunting strategies.