Illustration of the extinct canid Borophagus secundus baring its teeth. Borophagus secundus lived in North America during the Miocene epoch, between 23-5.3 million years ago. The adults are estimated to have been roughly similar in size to coyotes, but with a more powerful build with skulls adapted to crushing bone to extract nutrients. They may have gone extinct due to being outcompeted by felids (cats) and canines (subfamily of canid).