The Dusky dolphin is a species of dolphin which is only found in the Southern Hemisphere. It is similar both in appearance and genetic make up to the Pacific white- sided dolphin, but scientists and researchers have agreed that there are enough differences for it to be classed as its own species. The dusky dolphin is slightly smaller than average, with a body measuring around 6 feet. Males and females are extremely similar and there is almost no difference in size, weight or markings between the two sexes.
The dusky dolphin’s presence is patchy across the whole of the southern hemisphere. There are concentrated areas with larger populations off the coast of South America, New Zealand and Tasmania. They are prolific acrobats and are often seen giving some of the most impressive aerial displays in the dolphin world.
When it comes to mating season, the males try to impress the females by engaging them in a high-speed chase through the water. The females prefer the faster and more agile males, rather than the biggest or the most aggressive. Female dusky dolphins reach sexual maturity at the age of 6 or 7, the gestation period lasts around 13 months and females tend to give birth to a single calf every 2 and a half to 3 years.
The calves are nursed by their mothers in nursery groups for at least the first year of their lives. In this nursery group, the adult dolphins have been observed teaching younger calves how to hunt and catch fish.
The dusky dolphin’s conservation status is marked down as ‘data deficient’, simply because it is extremely difficult to measure the exact numbers of a species which has such concentrated populations in some areas and such sparse numbers in others. They are continually reported as being caught up in fishing and trawling nets off the coast of South America and it is believed that the population off the coast of Peru is highly at risk.
Dusky dolphins eat a wide variety of fish including anchovies, maceral, hake, sculpins, pilchards and lantern fish. Squid also make up a large part of their diet. The exact way in which they go about hunting depends on the exact location of that particular population, but they are coordinated hunters and tend to look for food in groups. They often use light reflected off their white bellies to direct and control schools of fish.