Evolutionary biologists have been arguing over seals' origins for more than a century. While relatively sure that pinnipeds evolved from land-dwelling carnivores, scientists are divided on the precise steps that occurred between terrestrial ancestors and modern marine mammals. Along with the three subclades of pinniped, the suborder Caniformia contains Ursidae (bears), Mustelidae (badgers, otters, weasels, and relatives), and Mephitidae (skunks and stink badgers). In 2007, a nearly complete skeleton of a new semi-aquatic carnivore from an early Miocene lake deposit in Nunavut, Canada, was discovered and became known as an evolutionary link between land mammals and seals.