A beautiful Fauna cover from México, depicting a complete set issued in 2015 celebrating the "vaquita" (Phocoena sinus).
The vaquita is arare species of porpoise endemic to the northern part of the Gulf of Califórnia. The vaquita is the most endangered cetacean in the world. It has been listed as critically endangered since 1996. The population was estimated at 600 in 1997, below 100 in 2014, approximately 30 in November 2016, leading to the conclusion that the species will soon be extinct unless drastic action is taken.