In recent years, a dramatic recovery in the population of bluefin tuna in the region has been a win for a group of about 40 critically endangered Iberian killer whales that feed exclusively on the large fish. This has meant they've cut down their time spent foraging, leaving space for other 'hobbies.' "In addition, climate change could be playing a role, leading to these tuna being in the Gulf of Cádiz continuously rather than seasonally," the scientists noted. "This year-round abundance means that there appears to no longer be a need for the whales to pursue every fish encountered."