Orcas Ram Sunfish So Hard They Explode in Newly Documented Behavior

Scientists have documented a previously unknown orca behavior: a cooperative 'stabilize-and-ram' technique that causes sunfish carcasses to explode into fragments. The findings were published Thursday in the journal Frontiers in Ethology.

What happened

In July 2024 and September 2025, orcas in the Gulf of California were filmed working in pairs. One orca held a sharptail sunfish by its tail while another charged at high speed, releasing the fish just before impact. The collision fragmented the carcass, with juveniles eating the smaller pieces and adults consuming the remains. Source: NPR Source: CNN

Possible explanations

Researchers propose two main hypotheses. Feeding facilitation: Sunfish have thick, rubbery skin and little meat, so ramming may break them into bite-sized pieces for young orcas or those with worn teeth. Source: NPR Play behavior: Orcas are known for playful antics, and the coordinated ramming shows elements of a social game. Source: The Guardian Co-author Erick Higuera notes that for behavior to be 'fun,' it must be voluntary and rewarding, which this may be. Source: Ars Technica

Unanswered questions

It remains unclear whether this is a cultural innovation limited to certain pods or a more widespread hunting strategy. Source: NPR More observations are needed to determine the primary function—whether it is strictly feeding, play, or both.