By st20113 
Introduction
The vaquita (Phocoena sinus) holds the tragic distinction of being the world’s most endangered marine cetacean. Found exclusively in the northern Gulf of California, this small porpoise has been driven toward extinction within a single human lifetime. First described in 1958, the vaquita remained poorly understood for decades, and by the time researchers grasped the severity of its decline, the population had already begun its catastrophic fall. By 2023, fewer than 10 individuals were estimated to remain. Unlike many endangered species, the vaquita cannot be saved through captive breeding—the species has never survived in captivity. Without eliminating the primary threat, the vaquita is expected to vanish within our generation.
Taxonomy
The vaquita belongs to the family Phocoenidae, the porpoises, classified within the genus Phocoena alongside the spectacled porpoise and Burmeister’s porpoise. Initially classified as a subspecies of the common porpoise, morphological and genetic studies formally recognized it as a distinct species in 1985. The species name sinus refers to the Gulf of California—the single body of water it inhabits. Its closest relatives are the Burmeister’s porpoise of South America and the spectacled porpoise of the Southern Hemisphere, neither sharing its range.
Physical Characteristics
The vaquita is the world’s second-smallest cetacean, with adults reaching lengths of just 1.2 to 1.5 meters and weighing approximately 30 to 55 kilograms. Its coloration is distinctive: a dark grayish-brown back transitioning to a lighter gray belly, with notable dark rings around each eye and dark patches on the lips that give the face a masked appearance. This facial marking is unique among phocoenids and one of the key features distinguishing it from other small cetaceans in its range. The dorsal fin is relatively tall and triangular, and the flippers are small and positioned well forward.
Habitat
The vaquita’s entire global range is limited to the northern Gulf of California—a semi-enclosed sea between the Baja California peninsula and mainland Mexico. The Gulf is a shallow, warm, productive body of water fed by the Colorado River delta, where nutrient-rich waters upwell from the deep. The Bottlenose Dolphin thrives in many of the same productive waters, but unlike that wide-ranging species, the vaquita cannot expand into new territory. The vaquita is typically found in water depths of 20 to 50 meters, within a few kilometers of the shore. Its extremely restricted distribution means any localized threat affects the entire species simultaneously.
Diet
Like other porpoises, the vaquita is a generalist carnivore feeding on small fish, cephalopods such as squid and octopus, and crustaceans found near the seafloor. Its spade-shaped teeth are adapted for grasping slippery prey in the murky waters of the Gulf. The Blue Whale shares the broader Gulf ecosystem but occupies a very different trophic niche, feeding on krill rather than demersal prey. Researchers believe the vaquita feeds primarily during daylight hours, and its diet reflects the abundance of small fish and invertebrates in the shallow coastal waters it inhabits.
Reproduction
Little is known about the vaquita’s reproductive biology given how rare sightings have become. Based on limited data, females are believed to give birth to a single calf every 1 to 2 years, with a gestation estimated at approximately 10 to 11 months. Calving appears to occur in spring or early summer. Like all small cetaceans, vaquita calves are nursed for several months before weaning. The species’ slow reproductive rate means populations cannot recover quickly from even moderate mortality, making the current crisis devastating.
Conservation
The vaquita is classified as Critically Endangered by the IUCN, with fewer than 10 individuals believed to remain. The population was around 200 in the 1990s and plummeted to under 100 by 2015. The primary cause of death is incidental capture in gillnets set illegally to catch the totoaba—a large fish whose swim bladder commands extraordinary prices on the black market in China. Mexico declared a gillnet ban in 2015, but illegal fishing continues. The Green Sea Turtle has also benefited from stronger marine protections in the Gulf. Each lost individual is an irreplaceable blow to the species.
Fun Facts
The name “vaquita” is Spanish for “little cow,” a nod to the species’ small size and gentle appearance. The vaquita has the smallest range of any cetacean in the world—its entire global population fits within an area that could occupy a single large lake. It was formally recognized as a species only in 1985, relatively recently for a mammal. The dark eye rings that give the vaquita its masked look are visible even on newborn calves, and no other cetacean in the Gulf of California shares this feature, making identification relatively straightforward when individuals are encountered.