The vaquita (Phocoena sinus) is a small and very elusive porpoise that ranges in a limited geographical area in the Gulf of California, Mexico. Despite various efforts to conserve this critically endangered species, the latest research reveals that it may become extinct within a few years. Little is known of the vaquita as it was first scientifically described in 1958 and the first physical specimens were only recovered in 1985 when sighting surveys were also begun. A review of the little known and available knowledge on its biology, habitat, and physiology was compiled to better understand and recognise how truly unique this species is. After more than 5 decades since its discovery, if the current trends continue, it would seem that the only knowledge about the vaquita will be the very few photographs ever taken and some specimens recovered as bycatch.