Marine researcher Emily Yeager discussed a peculiar behavior of suckerfish, also known as remoras, in an interview. These small fish hitch rides on larger marine animals like sharks, whales, and manta rays to feed on parasites in exchange for the transportation. However, recent research suggests that this relationship may not be entirely beneficial for manta rays.
Yeager, a PhD candidate at the University of Miami, led a study published in the journal Ecology and Evolution, revealing a phenomenon known as “cloacal diving.” This behavior involves the fish diving into the host’s cloaca, a body orifice for both reproduction and waste elimination.
While cloacal diving has been observed between remoras and whale sharks in the past, this study presents the first documented instances of this behavior between remoras and manta rays. Researchers documented seven such occurrences over 15 years, but they believe it happens more frequently than reported.
Yeager explained that remoras may engage in cloacal diving as a fear response, as observed in a video where a startled remora quickly dived into a manta ray’s cloaca. Brooke Flammang, a biological sciences professor, suggested that this behavior, known as coprophagy, might indicate the fish seeking food.
The potential harm caused by cloacal diving to manta rays raises questions about the nature of their relationship with remoras. Yeager highlighted that this behavior could lead to severe damage in sensitive areas and impact reproduction and waste elimination for the manta ray.
The study challenges the traditional classification of the relationship between remoras and manta rays as symbiotic or commensal, suggesting that nature’s relationships may be more complex than previously thought, existing on a spectrum of interactions.