Trending Now - Remoras: the Fish That Ride Manta Rays in Unusual Places
WHO:
Yahoo News UK - Emily A. Yeager, PhD student at the University of Miami, led the study on remora behavior.
The Seattle Times - Catherine Macdonald, director of the shark research and conservation program at the University of Miami, is the senior author of the study.
The Seattle Times - Eleanor Caves, a sensory biologist at Brown University, commented on the study but was not affiliated with it.
WHAT:
Live Science - The study documented an observation where a common remora quickly inserted itself into the cloacal opening of an adult Atlantic manta ray, which appeared bothered by the intrusion, shuddering before swimming away with the remora still inside.
Live Science - The study found that remoras were recorded inside the cloaca of a female manta ray, nicknamed Ms. Pac-Man, in October 2025 in Florida, USA.
The Seattle Times - The researchers noted that in some instances, the remora forced itself so far inside the ray’s cloaca that only the very tip of its tail was visible, while in other cases, half of the remora hung out of the ray.
Yahoo News UK - A new study documented remoras engaging in "cloacal diving behavior" in manta rays.
The Seattle Times - The study published in the journal Ecology and Evolution documented seven instances of cloacal diving behavior.
Yahoo News UK - Remoras were observed entering the cloaca of manta rays, which is used for digestion and reproduction.
The Seattle Times - The observations occurred across all three known species of manta ray: reef manta ray, giant oceanic manta ray, and Atlantic manta ray.
WHERE:
Yahoo News UK - The study was conducted across multiple ocean basins.
The Seattle Times - The observations took place in three separate ocean basins.
WHEN:
The Seattle Times - The instances of cloacal diving were recorded between 2010 and 2025.
WHY:
Live Science - Emily Yeager stated that the remora's ability to remove itself from the manta ray is likely very limited, suggesting that the relationship may not be harmless for the manta.
Yahoo News UK - The study raises questions about the potential harmful effects of remoras on manta rays, which are already vulnerable due to fishing pressure, boat strikes, habitat degradation, and climate change.
The Seattle Times - The behavior of cloacal diving may interfere with waste discharge or reproduction in manta rays, suggesting a shift from mutualism to parasitism.
HOW:
Live Science - Yeager collected data from manta ray scientists around the world, finding that cloacal diving was recorded seven times over 15 years, indicating it is likely a widespread behavior but rarely seen.
Yahoo News UK - The researchers recorded observations of remoras engaging in cloacal diving behavior.
The Seattle Times - The study utilized seven documented instances to analyze the behavior of remoras in relation to manta rays.
(UPDATED May 13, 2026 07:51 UTC)
A recent study has revealed a fascinating observation of a common remora inserting itself into the cloacal opening of an adult Atlantic manta ray, which seemed distressed by the intrusion. This behavior was documented in October 2025, when researchers noted that a female manta ray, affectionately named Ms. Pac-Man, had remoras recorded inside her cloaca, sometimes with only the tip of the remora's tail visible. Emily Yeager, who gathered data from manta ray scientists worldwide, highlighted that while this cloacal diving behavior appears to be widespread, it is rarely observed, raising questions about the potential risks for the manta ray involved.
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(UPDATED May 12, 2026 23:25 UTC)
A new study led by Emily A. Yeager, a PhD student at the University of Miami, has documented remoras engaging in a behavior known as "cloacal diving" in manta rays, with observations recorded across multiple ocean basins. The research, which includes seven instances of this behavior, raises concerns about the potential harmful effects of remoras on manta rays, which are already facing threats from fishing pressure and climate change. Senior author Catherine Macdonald, also from the University of Miami, highlighted that this behavior could indicate a shift from mutualism to parasitism, potentially interfering with the manta rays' waste discharge and reproduction.