Common sources of meat during this time included woolly mammoth, bison, and elk. Ice Age humans were indeed hunter-gatherers, and they had to work together in order to find food and survive.

Not until the late 19th century did humans learn of the extraordinary art produced by their Ice Age ancestors ... of prey and predator animals -- bison, deer, bears, cattle, mammoths, and reindeer ...

Prey in the ice age was plentiful; horses ... ideal for killing large prey like camels, horses, and bison. Some experts think they would take down a small mastodon from time to time.