Marine scientist Emily Yeager revealed in an interview that suckerfish, also known as remoras, are not always considerate travel companions. These small fish hitch rides on larger marine animals like sharks, whales, and manta rays to feed on parasites in exchange for transportation. However, recent research indicates that having a remora attached to a manta ray may pose discomfort for the latter.
Yeager, a marine researcher at the University of Miami and the lead author of a new study published in the journal Ecology and Evolution, discussed a behavior she termed “cloacal diving.” This term refers to remoras launching themselves into the cloaca of their hosts, which serves as a single orifice for reproduction and waste elimination.
While this behavior has been observed between remoras and whale sharks before, the interactions with manta rays have not been documented until now. Researchers identified seven instances of cloacal diving over a 15-year period in various ocean locations, suggesting it may occur more frequently than observed.
Yeager speculated that the remoras’ behavior might be a response to fear, triggered by external stimuli like divers. Video evidence showed a remora diving into a manta ray’s cloaca after being startled, causing the ray to react violently before resuming its activities.
According to Brooke Flammang, a professor of biological sciences, the cloacal diving behavior could stem from the remoras seeking food, even if it involves consuming waste material (coprophagy). Flammang noted that remoras can be territorial when sharing hosts and are known for their unconventional behaviors.
While the impact on manta rays remains uncertain, Yeager suggested that the suction cup attachments of remoras could potentially harm the ray’s cloaca, affecting its reproductive and waste elimination functions. This complication challenges the traditional classifications of symbiotic or commensal relationships between species, emphasizing the complexity of nature’s interactions.
The unique behavior of remoras continues to intrigue researchers, highlighting the need to further understand the dynamics between these species for conservation and ecological studies.
