An Invented Hunting Tactic
In the clear waters of Jurien Bay Marine Park, a population of Australian sea lions (Neophoca cinerea) has developed a hunting technique previously unknown to science. These animals, typically solitary foragers, have been observed working in teams to hunt octopus. This cooperative strategy is a learned behavior, not an instinct, and appears to be spreading through the local population—a case of cultural transmission in a marine mammal.
The technique is a direct response to the challenge of their prey. Octopuses are adept at hiding in the park's complex limestone reef systems. To counter this, a group of sea lions coordinates its attack. Several sea lions will patrol one side of a long, narrow rock ledge, while another group moves to the opposite end. The first group then uses its bodies and flippers to thrash and flush the hidden octopus out from under the ledge, driving it directly toward the waiting ambush of the other sea lions. This method allows them to catch prey that would be difficult for a single hunter to secure.
This behavior is specific to the sea lion population in this area. Australian sea lions elsewhere are benthic foragers, meaning they hunt for prey like fish, squid, and crustaceans alone on the seafloor, often diving to depths between 40 and 80 meters. The appearance of this collaborative strategy in Jurien Bay shows a capacity for social learning and adaptation.
An Endangered Innovator
The Australian sea lion is one of the rarest sea lion species in the world, with a total population estimated at less than 12,000. The species is listed as Endangered, facing threats from fishery interactions and habitat degradation. The population in Jurien Bay Marine Park is genetically distinct and represents the only breeding colony for the species on the entire west coast of Australia.
The park's unique underwater geography likely influenced the development of this hunting culture. The extensive limestone reefs, which run parallel to the coast, are riddled with caves, overhangs, and ledges that provide perfect hiding spots for octopus and western rock lobster. It is within this specific environment that the sea lions innovated their solution.
Researchers from institutions like the University of Western Australia study these animals to understand their behavior and inform conservation efforts. The collaborative foraging is of particular interest because it demonstrates how animal populations can develop new traditions to exploit available food sources, a level of behavioral flexibility that may be important for their survival in a changing ocean.