Since the baiji (Lipotes vexillifer
) was believed to have become extinct in 2006 (3), the vaquita has taken on the unfortunate title as the most endangered cetacean in the world (4). It also has the distinction of being the smallest porpoise species (2), a group of marine mammals that differ from dolphins in their stockier, robust body, lack of an elongated beak, and their distinctively shaped teeth (5). The vaquita has a dark grey back and pale grey sides, blending into white on the underside, and there are highly conspicuous large black rings around its eyes and mouth. The fin on the back of its body, the dorsal fin, is proportionally taller than that of other porpoises and is roughly triangular, but curves slightly backwards (6).