If you're referring to the climbing then I can honestly say it's much less of a resource thing but more of a "climbing system" trade-of. Sifaka's very much "hug" branches when they climb which doesn't work well in a game where you can make any climbing frame you want out of any climable pieces that are of different widths. Even at the peak of the game's development a sifaka most likely would have always climbed like the rest of the lemurs. Like, even koalas ingame struggle with it and don't always look good, and I'm pretty sure that's the reason why sloths were made as exhibit animals as well.
It's a trade-off, one of which I'm aware that not everyone likes and some people go as far as saying that it shouldn't have been in the game; but I'd rather have sifaka's that don't climb exactly like they would in real life if that means we can have the flexible climbing system we have today (as much as I curse it sometimes because of it black-box nature haha).
I tend to agree with Mjmannella, I wouldn't go as far as NA to make the point as there sure have been animals with equal amount of complexity since then; but the game has certainly reached a point where very few land and semi-aquatic based animals are completely out of bounds or require massive amounts of resources to make. There's an incredible library of animations and behaviors they have to start from, and software that allows them to speed up the process of reusing that library.
At this point in time, I can barely think of any animal that wouldn't fall into the "reuses an altered existing rig and animation set with some extra animations" category, with the work that Frontier has put in so far pretty much nothing in terms of land and semi-aquatic animals is impossible or resource intensive.
I'm going to tell
@TheDuckKnight you hate ducks
@Aramar .