By the start of the Eocene Epoch about 56 million years ago, North America was also home to omomyiforms, a group of tarsier-like primates, and adapiforms, which were more lemur-like.

到大约 5600 万年前的始新世开始时，北美也是 omomyiforms（一群像眼镜猴的灵长类动物）和 adapiforms（更像狐猴）的家园。