Rorquals are the largest group of baleen whales, comprising the family Balaenopteridae, which contains nine extant species in two genera. They include the largest animal ever known to have lived, the

Eschrichtiidae or the gray whales is a family of baleen whale with a single extant species, the gray whale, as well as four described fossil genera: Archaeschrichtius, Glaucabalaena and Eschrichtioide