Xisca Nicolas wrote:omnivores cannot survive ice age if herbivores do not!!! What would they eat?
It gets reduced to specialists. Compare:
African veldt: harsh but hot. Grass, brush, trees
. ~40 species of large herbivore (antelope to elephants), half a dozen large carnivores, food chains flexible and numerous.
Arctic tundra: harsh but cold. The large-animal food chains are: lichens, caribou, wolves; ocean fish, seals, polar bears (who sometimes eat wolves). That's it, all of it.