Marine researcher Emily Yeager discussed a recent study revealing the not-so-considerate behavior of remoras, also known as suckerfish, toward manta rays. Remoras hitch rides on larger marine animals, feeding on parasites in exchange. However, the study suggests that this relationship may have downsides for the manta rays due to a behavior termed “cloacal diving.”
Cloacal diving involves remoras diving into the cloaca of their host, which serves as a reproductive and excretory outlet. While this behavior has been observed between remoras and whale sharks before, this study marks the first documented evidence of such interactions between remoras and manta rays.
The study, led by Emily Yeager and published in the journal Ecology and Evolution, documented seven instances of cloacal diving over a 15-year span. However, researchers believe this behavior likely occurs more frequently than reported.
According to Yeager, the diving behavior may be a fear response by the remoras, as observed in a video where a remora swiftly enters a manta ray’s cloaca after being startled. Brooke Flammang, a biological sciences professor, suggests that the behavior might be driven by the remoras seeking food.
The consequences of cloacal diving on manta rays remain uncertain. Yeager expressed concerns about potential skin damage and reproductive issues caused by remoras’ suction cups. This behavior challenges the traditional categorization of the relationship between these species as either symbiotic or commensal, suggesting that nature’s interactions are more complex and varied than previously thought.
