Chilean Dolphin

The Chilean dolphin is small at around 1.7 metres (5 ft 7 in) in length, with a blunt head. Adults reach up to 60 kg, with females slightly larger than the male bulls. This dolphin is thickly shaped with its girth up to two-thirds its length. Their small and thick shape is often mistaken for other types of porpoises. The dorsal fin and flippers are small in proportion to body size in comparison with other dolphins. The throat, underside, and the closest part of the flippers to the body are white. The remainder of the body is a mix of greys. A black line connects their blowhole, eyes, and dorsal fin. It has 28–34 pairs of teeth in the upper jaw and 29–33 in the lower. The two eyes are positioned at the ends of the mouth lines, giving the appearance of a smile. The tail has a characteristic notch in the middle.

The population of the Chilean dolphin, perhaps one of the least studied of all cetaceans, is not known with certainty. It is estimated that less than 5,000 Chilean dolphins remain in the wild. Whatever its number, the Chilean dolphin is endemic to the coast of Chile, meaning it is no found anywhere else in the world. They are believed to not migrate. The dolphin is seen over a wider interval of latitudes than other Cephalorhynchus species – from Valparaíso at 33°S to Cape Horn at 55°S. Larger groups of 20-–50 are found in the northern areas of its habitat, including reports of a 24-kilometre-long (15 mi) pod. However, the majority of the Chilean dolphins population is found in the southern regions. The species prefers shallow water regions, specifically areas near rivers and high tides.

The Chilean dolphin primarily feeds on sardines, anchovies, salmon, squid, crustaceans, and green algae. They swim in a circular or zig-zag pattern to herd the fish that they eat.

Unlike other types of dolphins that commonly exhibit social behavior, the Chilean dolphin often remains distant during possible encounters with humans. The Chilean dolphin is normally sighted in small groups of around two to ten individuals, with some larger gatherings of up to 50 individuals occasionally sighted. A group of dolphins is referred to as a pod, school, or herd. The species exhibits epimeletic behavior, meaning that when one individual in the pod is injured or sick, healthy members will help take care of the sick.

Little is known about the reproduction of the Chilean dolphin. They mate in the early winter and females give birth to their offspring in the spring. Female dolphins, known as cows, usually have one calf every two to three years. Calves reach full maturity between ages 5 and 9 years. Young calves are cared for by their mothers, where they learn to forage and navigate social behavior.

Humans pose the largest threat to the Chilean dolphin population. In addition to being caught for human consumption, the dolphins are also used as bait for long-line sword fishing and crab fisheries. It is reported that between 1,300 and 1,500 Chilean dolphins are harpooned in the Strait of Magellan each year. Use as bait was particularly popular until the 1990s, and hunting of Chilean dolphins is now illegal. Aquaculture farms for salmon, anti-sea lion nets, and boat traffic also pose as threats to the species. Since 2023, at least 14 Chilean dolphins have died as a result of widespread bird flu in Chile. Reports indicate that Chilean dolphins are preyed upon by killer whales and sharks. The increase of human activity near the Chilean coastline has also degraded the fragile shallow water habitat.