Scientific Classification
KINGDOM:Â Animalia
PHYLUM: Chordata
CLASS: Mammalia
ORDER: Artiodactyla
FAMILY: Delphinidae
GENUS: Lagenorhynchus
SPECIES: H. inermis
Conservation Status
The dusky dolphin is a smaller dolphin compared to others in its family. They can reach a length of 5-7 feet and weigh 150-190 pounds depending on gender and location.
The dusky dolphin has a characteristically small beak, which is dark gray surrounded by white. This white covers the throat and stomach as well as a patch between the dorsal fin and tail. The rest of their body is mixed with tones of grays and blacks.
Dusky dolphins also have two horizontal tail flukes and a curved, tall dorsal fin.
The dusky dolphin is a compact dolphin found throughout the Southern Hemisphere. There are 4 subspecies all located in the cool currents around areas such as South America, Africa, Australia, New Zealand, and more. They are closely related genetically to the Pacific white-sided dolphin, which can also be found in the Southern Hemisphere, but have recently been declared a separate species.
Dusky dolphins are carnivores with cone-shaped teeth that help them grasp onto slippery prey such as squid, sardines, anchovies, cod, and other fish. Like most dolphins, echolocation and their excellent eyesight and hearing makes them great predators. They adapt their foraging style to their environment like hunting at night in deeper waters while hunting during the day in shallow waters. However, dusky dolphins prefer the shallow waters to avoid being eaten by killer whales.
The mating season for the dusky dolphin varies regionally but tends to align with spring. Both males and females will have multiple partners since females can only birth one calf. Once ready to mate, a female will make the males chase her until one is left as they prefer mates with speed instead of strength or aggression. The female will remain pregnant for just over 12 months before giving birth to a 20-40-pound calf! Dusky dolphin mothers meet together in nursery groups to rest and care for each other.
Dolphins are known to make three different types of sounds which are click trains, burst pulses, and whistles; in fact, dusky dolphins can make all three sounds. Click trains are made with several quick clicks moving from low to high. Burst pulses are also individual clicks but with one high, continuous note; these pulses can be heard with the human ear but only as a faint buzzing sound. A whistle is a single pure tone that varies in frequency throughout the day.
Their pods are usually made up of 10-20 individuals.