Orcas have long been revered for their intelligence, adaptability, and group-hunting strategies. But one scientific review spanning two decades has revealed a little-known, yet intriguing behavior. Researchers observed orcas across six separate populations ...

Pacific white-sided dolphins swim off the coast of British Columbia. Dolphins and porpoises in this region have been spotted swimming alongside a population of killer whales known as northern resident orcas. Scientists have theories about why. Photograph ...