The name “Pygmy killer whale” comes from the fact that this dolphin shares specific physical characteristics with killer whales.
However, this marine mammal is not closely related to the killer whale species, regardless of its physical appearance.
Pygmy, in particular, means “short” or “lesser” and is used to describe smaller versions of cetaceans that appear similar in physical appearance to their larger relatives.
While these dolphins are sometimes hard to spot, they are typically found in warmer tropical and subtropical environments in and around the equator.
Unlike the killer whale, this species is much smaller in size and weight (about the size and weight of an average dolphin).
They have displayed extreme aggression towards other marine mammals when close to other species.
Physical Characteristics and Appearance
The Pygmy killer whale can reach an average size of 6 – 8.5 ft in length and weigh between 250 – 400 lbs when fully matured.
As stated earlier, one of the resembling features these marine animals share with the killer whale is skin coloring, which is black to dark grey with lighter colored (whitish) markings on the under-body and lower jaw.
They have rounded skulls with large canonical teeth, but the pygmy killer whale lacks a snout or beak, unlike other dolphin species.
Another common feature this dolphin shares with the killer whale is its long angular dorsal fin, which can often be seen leaning to one side.
Diet and Hunting Methods
The pygmy killer whale eats various fish, octopus, and squid.
However, its hunting methods have not been well-researched.
They have also occasionally attacked other marine mammals, usually small marine animals such as dolphins.
Habitat and Migration
These dolphins prefer living in tropical/subtropical climates.
They can be seen in places such as Hawaii, the Indian Ocean, the Northern Gulf of Mexico, Sri Lanka, Japan, the Northern West Atlantic, and occasional spottings in the United States and South Carolina.
Compared to other species, the pygmy killer whale prefers living in deeper offshore oceanic waters rather than near coastal areas or inshore waters.
Social Structure and Communication
From what is known about this dolphin’s social structure, they tend to travel in groups of 10 – 30 dolphins, with groups growing well beyond 30 during certain social events.
Observations show that these dolphins can be reasonably aggressive in certain aggregations.
When brought into captivity, some dolphins displayed so much aggression that they began killing other marine mammals in the group.
Mating, Reproduction and Lifespan
While not much is known about the pygmy killer whales’ breeding habits, it can be estimated that the average gestation period for these mammals is likely to be 10 – 12 months.
As with other dolphins, these mammals most likely feed their young with milk for several months to a year while the baby dolphin learns to hunt and consume solid foods.
Both the Sexual maturity and lifespan of the pygmy killer whale are unknown.
However, most dolphin species reach sexual maturity between 6 and 12, with a few dolphins waiting until around 15 to begin reproducing offspring.
Threats and Predators
The pygmy killer whale doesn’t appear to face many threats other than accidental catches in fishing nets, which can occur when a dolphin sees a large group of fish and goes in for the kill, assuming its easy prey, or in cases where the dolphin did not notice the fishing net that was cast in the ocean.