Despite their reputation as 'killer' whales, orcas are known to lend a helping fin by sharing their food with humans. A recent study recorded and analyzed 34 instances of prey-sharing by orcas (Orcinus orca) across two decades of observation.
Orcas, the largest members of the dolphin family, are widespread across all the oceans and engage in a variety of complex social behaviors. They have a rich culture and communicate using unique calls.
They also live in matrilineal societies in which older females model social behaviors for the younger members, influencing what they eat, do for fun, and who they mate with – as matriarchs may do in human societies. And, of course, orcas wear salmon hats and fashion kelp-based tools for their beauty routines.
Altruistic behaviors are common among orca communities. They commonly share food with their cetacean companions and family members as a "prosocial activity and a way [to] build relationships with each other," says lead author Jared Towers, ecologist at Bay Cetology in Canada.
The fact that they "share with humans may show their interest in relating to us as well."
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The study spanned two decades and recorded dozens of instances in which wild orcas shared prey with humans. As criteria for inclusion, these interactions had to have been instigated by the whales, and not a result of humans approaching orcas. The interactions were either captured on video, in photos, or described to the researchers via interviews.
Of the 34 total recorded interactions, 21 involved people on boats, 11 involved people in the water, and 2 involved people on the shore. The orcas spanned both sexes and all age groups.
As another part of the inclusion criteria, the whales had to intentionally release the food in front of humans, from about one-orca-body-length away. Sometimes, the orcas played with the food items before releasing them.
About two-thirds of the time the orcas approached alone, but occasionally they approached in pairs and less often in groups. In half of the 34 interactions, the orcas offered an entire food item, such as a whole seal. In all but one of the cases the whales waited, for a median time of five seconds, to see what would happen after making their offering.
Ostensibly to the orcas' chagrin – but absolutely advised for ethics and cross-species safety – the humans ignored the offerings in 30 of the 34 recorded interactions. Still, some of the orcas made additional attempts to offer the food item. One can't blame an orca for trying.
It's possible that this interspecies prey-sharing is even more common than the study suggests, because this research only included examples based on strict criteria. Furthermore, these interactions may become increasingly common as human and orca activities begin to overlap more frequently.
Similar sharing behaviors have been previously observed in domesticated animals, like cats and dogs who sometimes split their food with their furless, bipedal friends. But this study is a rare groundbreaker that investigates sharing attempts from non-domesticated animals. As the researchers explain, "accounts of any wild animals attempting to provision humans are extremely rare."
Why are orcas so seemingly eager to share with humans? Perhaps to explore, play, and develop relationships with a curious brand of beings. Given the "advanced cognitive abilities and social, cooperative nature of this species," maybe orcas are attempting to forge cross-boundary relations. After all, stories of dolphins saving humans stretch back into antiquity.
Plus, orcas commonly hunt large prey, with diminishing returns when they end up with more food than they can consume, transport, or preserve.
And there's no clear risk of competition: orcas and humans are both apex predators but in "drastically different biomes." Accordingly, there are very few examples of wild terrestrial predators sharing surplus food with humans.
The researchers conclude that generalized altruism and reciprocity are cultural by-products of prosocial species. These behaviors are also social cornerstones associated with high levels of encephalization, or larger-than-expected brain size in relation to body size. In fact, orcas are second only to humans in this respect, say the study authors.
Therefore, these food-sharing interactions are a novel example that highlights an evolutionary and intellectual convergence, between the highest branches of the primate and cetacean trees of life.
This study was published in the Journal of Comparative Psychology.