Each spring, hundreds of thousands of cownose rays (Rhinoptera bonasus) migrate from the Florida waters into the Chesapeake Bay. Rays belong to a group known as Chondrichthyes, characterized by possessing cartilage, not true bone. One of the most unusual characteristics of the cownose ray is live birth of their young instead of depositing eggs like most aquatic species. The females give birth to their young in the calm estuarine waters of the Bay, and all the stingrays remain in the Chesapeake until October.