14 DAY TRIAL // According to existing classifications, killer whales, or orcas, are all lumped together in a single species, but a new genetic research would seem to indicate the existence of at least four species. Researchers say that marked differences exist between the ways these groups of animals live, hunt, and speak, as well as between the areas they prefer to live in. Orcas are among the most renowned whales, though they are actually the largest dolphins nowadays.
These creatures are very intelligent, as evidenced by the fact that they hunt in packs, similar to wolves. They can defeat and feast on great white sharks, the fearsome predators of the sea, as well as on blue whales, which are at this point the most massive creatures on the face of the planet. In spite of being smaller than other whales, their bodies are very powerful, and they form strong social hierarchies. They also possess an intricate “vocabulary,” which they use to communicate with each other, within a group.
For many years, experts have been proposing that the animals be classified in several species, based on minute differences in appearance and behavior. Some areas, such as the North Pacific, exhibit clearly different groups. Here, resident, transient and offshore orcas are the most common. In the Southern Ocean, around Antarctica, type-A, type-B, and type-C killer whales can also be distinguished from each other with a little bit of practice. In order to investigate the genetic foundation for these differences, researchers at the La Jolla, California-based Southwest Fisheries Science Center, an institute of the US National Oceanic and Atmospheric Administration (NOAA), looked at samples from 139 orcas.
Using an investigations method known as highly parallel sequencing, the investigators looked at the mitochondrial DNA in all samples, which were gathered from orca populations around the world. According to SFSC expert Phillip Morin, “we were able to see clear differences among the species.” In a paper appearing in the April 22 issue of the respected scientific journal Genome Research, the experts say that type-B and type-C killer whales are definitely separate species, from themselves and from type-A, while the same also holds true for transient orcas. “We need more samples to tell. And collecting information on killer whales in the wild is really difficult,” Morin says.
The findings could have broader implications, especially when it comes to looking at whether the animals are endangered or not. “If you think of them as one global species, they're not threatened, but if you look at them as many different species, the multiple, smaller populations of killer whales that result could be seen as endangered,” the expert concludes, quoted by LiveScience.