Scientists Caught Suckerfish Diving Into Manta Rays' Rear Ends

Marine biologists found seven rare cases from 2010 to 2025 where remoras entered manta ray cloacas, a newly named behavior called cloacal diving.

The observations came from global manta footage and were reported by Emily Yeager and colleagues in Ecology and Evolution.

Remoras may use the maneuver to avoid predators or gain access to the rays’ bodies, but the behavior could also stress the host.

Researchers say the interaction may be more than harmless hitchhiking and could affect manta ray health, waste removal, or reproduction.