User blog comment:ASDFGirl/The Future of Fossils and Archeology: Revival/@comment-2804:14D:7882:84DA:145E:7BEC:8122:9161-20180523001815/@comment-25118285-20180523215812

We removed the biome variants for a couple different reasons: One, because its not really natural to hatch an animal and have it magically, automatically adopt a color pattern based on the current location. Second, since we implemented sexual dimorphism, that would mean there would need to be even more textures. Say an animal has one texture for male, one for female, and one for infant; create two variants of that mob, and that's six textures! It's more work than it's worth. We may see things like albinism and melanism at some point, but I can't say for sure.