mob variants depending on biome

while I was playing I realized something, there are many biomes, but in all the biomes, no matter how different they are, the mobs have the same style, a cow that lives on a snowy mountain at -15 degrees has the same fur as a cow that lives pleasantly in a meadow, so I had the idea that the mobs appear with different styles depending on the biome, ex: a cow that appears in a snowy biome would have a style similar to thick fur that would clearly withstand low temperatures, but a cow that appears in a jungle/grassland would have a similar style to a smaller fur, the same way for pigs and even chickens (I don't know how chickens would work in that sense) although it would also be very cool to see a zombie/pillager with a skin similar to a coat for being in a snowy biome