What's happened
Researchers have recorded remoras performing cloacal diving into manta rays, a behavior possibly more parasitic than mutual. The finding, spanning seven instances across three basins, prompts questions about the frequency and impact on manta cloacal function and reproduction.
What's behind the headline?
What this means for readers
- This behavior expands our understanding of remora-host interactions beyond traditional cleaning roles.
- It may indicate a spectrum of symbiosis from mutualism to parasitism, influenced by context and host health.
- The observations across multiple basins suggest the behavior is not isolated to a single swamp or region, pointing to broader ecological dynamics between remoras and manta rays.
Potential implications
- If cloacal diving affects manta reproduction or waste excretion, long-term fitness consequences could alter manta populations.
- Future research should quantify frequency, triggers, and physiological effects on hosts to assess population-level impact.
Caveats for readers
- The sample size is small (seven events); broader surveillance is needed to establish prevalence.
How we got here
The new study, published in Ecology and Evolution, documents seven observed cloacal dives by remoras on manta rays between 2010 and 2025, expanding prior observations that involved whale sharks. This raises questions about the prevalence of this behavior and its ecological significance.
Our analysis
New York Times reported seven instances of cloacal diving across three manta ray species and basins, citing University of Miami researchers. NY Post summarizes similar observations and speculates on mating and coprophagy motivations, while The Guardian covers the companion context of whale-gazing behavior and citizen science contributions.
Go deeper
- What evidence exists that cloacal diving affects manta ray reproduction?
- How common is cloacal diving across manta species and ocean basins?
- What methods are researchers using to monitor this behavior long-term?
More on these topics
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Remora - Fish
The remora, sometimes called suckerfish, is any of a family of ray-finned fish in the order Carangiformes. Depending on species, they grow to 30–110 cm long.
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University of Miami - Private university in Coral Gables, Florida, United States
The University of Miami (UM, UMiami, Miami, U of M, and The U) is a private research university in Coral Gables, Florida, United States. As of 2024, the university enrolled 19,852 students in two colleges and ten schools across over 350 academic majors...