About rhinos, the differences beside colors is that a black one has a hooked nose while a white one has a wider and squarish nose.
Fun fact - this is because white rhinos are grass grazers and live on open plains, whereas black rhinos are very shy, hide in forests and nibble leaves. Their necks are raised and their beak-like lips are perfect for curling around small branches.
Fun fact 2: when startled, a white rhino with young will sprint away with its babies in front of it, so it can shield them from whatever is behind. A black rhino will charge away in front of its babies, clearing a path through the forest. This strategy actually matches the type of predator: a leopard in the forest is an ambush predator and won't give much chase, so the black rhino just has to get their baby away asap. A pride of lions that might attempt a baby white rhino will chase, but can be scared off by a parent who turns around and shows its horns.
FF3: White rhinos enjoy company and are usually seen surrounded by zebra, wildebeest, warthogs and cranes. Black rhinos are extremely secretive and quiet and stay away from other animals that might attract attention.
Learned all this in South Africa last year

saw lots of white rhinos but wasn't lucky enough to see a black one, but heard one a couple of times. Was lovely just to know I was in their presence.
I wish the in-game animals had different behaviours like this, then having both species would be more interesting for people.
Pic I took -