Altruistic behaviors such as prey sharing are prosocial acts that can instigate and perpetuate various forms of reciprocity. Subsequent relationship dynamics provide a foundation for the evolution of societal norms and associated encephalization in social taxa, like primates and dolphins.
Some cultures within these families benefit from interactions with other mammal species but accounts of any wild animals attempting to provision humans are extremely rare.
In this article, we present 34 cases of both sexes and all age classes of killer whales (Orcinus orca) offering prey and other items to people who were on boats (n = 21), in the water (n = 11), and on shore (n = 2) in four oceans.
A total of 18 species were offered—six fishes, five mammals, three invertebrates, two birds, one reptile, and one seaweed.
In almost every case the whales awaited a human response before subsequently reacting.
The occurrence of these events suggests a limited cost to exploratory behaviors in some populations of this species.
We suggest these apparently nonrandom cases may be representative of interspecific generalized altruism.
This behavior may represent some of the first accounts of any wild predator intentionally using prey and other items to directly explore human behavior and thus may highlight the evolutionary convergence of intellect between highest order primates and dolphins.