In a recent study led by marine researcher Emily Yeager from the University of Miami, it was revealed that remoras, also known as suckerfish, are engaging in an unusual behavior called “cloacal diving” with manta rays. These small fish hitch a ride on larger marine animals, such as manta rays, to feed on parasites. However, the study suggests that this behavior may pose discomfort to the manta rays.
The phenomenon of cloacal diving involves the remoras launching themselves into the cloaca of the manta rays, which serves as a multipurpose opening for reproduction and waste excretion. While similar behavior has been observed between remoras and whale sharks in the past, this is the first documented evidence of such interactions between remoras and manta rays.
The study documented seven instances of cloacal diving over 15 years in various ocean locations, implying that this behavior may be more common than currently known. The researchers believe that the remoras may resort to this action as a response to fear, as seen in a video where a remora quickly dives into a manta ray’s cloaca after being startled by a diver.
Brooke Flammang, a biological sciences professor, suggests that the remoras might be engaging in coprophagy, or the consumption of feces, while seeking a potential food source. Despite the unusual nature of this behavior, Flammang mentions that remoras can exhibit territorial behavior when sharing a host.
The potential harm caused by cloacal diving to the manta rays raises questions about the classification of the relationship between the two species. Typically viewed as either symbiotic or commensal, this behavior challenges the traditional categorization and suggests that natural relationships exist on a spectrum.
The impact of cloacal diving on the manta rays’ well-being remains unclear, but Yeager speculates that it could lead to severe damage, particularly in the sensitive cloaca area. This discovery adds complexity to the understanding of interspecies relationships in marine ecosystems, highlighting the intricate dynamics that exist within nature.
