In a groundbreaking discovery that broadens our understanding of marine life communication, researchers at Oregon State University have identified a novel chemical signaling mechanism among bat rays (Myliobatis californica) that warns conspecifics of looming threats. This chemical disturbance cue, previously documented only in bony fish, now emerges as a key anti-predator strategy in cartilaginous fishes—specifically rays—revealing a layer of behavioral complexity that challenges long-held assumptions about elasmobranch social interactions.

Dr. Joshua Bowman, leading the study from OSU’s Big Fish Lab, devised an elegant experimental setup employing three isolated tanks interconnected through water flow but segregated visually and acoustically to eliminate confounding sensory influences. Each tank housed an individual bat ray, with one designated as the “signaler” and the other two as “receivers.” By simulating predatory pressure through a gentle chase of the signaler ray, the experimenters induced a natural defensive response while ensuring no physical harm.

Strikingly, within mere seconds of the signaler tank’s water being directed towards the receiver tanks, the bat rays in these isolated environments exhibited marked behavioral shifts characterized by increased swimming speed and evasive maneuvers. These responses mimic a flight reaction, confirming the transfer of a chemical alarm cue through the aquatic medium—a sensory pathway previously undocumented in cartilaginous species.

This discovery bears profound implications for understanding elasmobranch ecology and survival strategies. Bat rays, along with sharks and skates, belong to a class of cartilaginous fishes characterized by their distinct evolutionary lineage and physiology. These findings suggest sophisticated intraspecies chemical communication channels functioning as early-warning systems against predation risks, potentially reshaping our perception of their behavioral ecology.

Moreover, the research carries significance beyond bat rays. Whites sharks, apex predators renowned for their fearsome reputation, are known to exhibit avoidance behaviors when orcas, their potential predators, are nearby. Yet, these sharks often do not have direct visual contact with orcas. This study’s insights into chemical alarm signaling hint at unseen communication mechanisms that might underlie such evasive behavior, opening new avenues for exploration into shark sensory biology and their interactions within the marine predator-prey network.

The experiment’s methodological rigor enhances the credibility of these findings. By isolating variables—eliminating acoustic and visual cues—the team conclusively linked behavioral changes to chemical signals. High-resolution overhead video recordings captured nuanced shifts in locomotion dynamics, quantitatively analyzing the rays’ rapid swimming velocity increases immediately following exposure to the alarm chemicals. These data underscore a robust flight response triggered solely by chemical disturbance cues.

While the precise chemical compound or combination responsible for the alarm signaling remains unidentified, the study establishes a foundation for future biochemical and molecular investigations. Identifying the molecular structure of the alarm cue could unlock transformative understandings of elasmobranch chemical ecology, potentially informing conservation strategies and offering biomarkers for monitoring stress responses in marine populations.

Importantly, the research foregrounds broader ecological and ethical considerations. The evolutionary origin of these chemical disturbance cues underscores their critical role in survival and natural behavior modulation. Human interactions—whether through scientific research, fisheries, or recreational activities—may inadvertently trigger stress dissemination across populations via such chemical signals, amplifying disturbance impacts beyond the initially affected individual.

The OSU Big Fish Lab, recognized as a leading shark research facility on the U.S. West Coast, continues to spearhead innovative studies uncovering the intricate lives of marine cartilaginous fishes. This collaboration, involving co-authors Jamie Cornelius and Mauricio Cantor, integrates expertise spanning marine ecology, physiology, and animal behavior, thereby enhancing multidisciplinary perspectives crucial to advancing marine science frontiers.

By employing bat rays as a proxy for studying elusive white shark behavior, the researchers circumvent logistical challenges inherent to large predator studies. Bat rays’ accessibility and manageable size provide an ethical and practical model to dissect communication modalities applicable across related species, ensuring experimental feasibility while preserving ecological validity.

This study, recently published in the Journal of Experimental Zoology Part A: Ecological and Integrative Physiology, represents a significant milestone in marine biology. It not only documents, for the first time, chemically mediated disturbance cues in cartilaginous fishes but also stimulates critical reflection on the sensory worlds of sharks and rays, organisms whose behavioral sophistication may be far richer than previously appreciated.

Collectively, these findings herald a paradigm shift in our understanding of underwater communication networks. They remind us that aquatic ecosystems host complex, often hidden, language systems integral to species survival. As we deepen our inquiry into these chemical dialogues, we unlock new insights essential for protecting marine biodiversity in a rapidly changing ocean environment.

Subject of Research: Animals
Article Title: Behavioral Evidence for a Chemical Disturbance Cue in Bat Rays (Myliobatis californica)
News Publication Date: 10-Jun-2026
Web References: http://dx.doi.org/10.1002/jez.70102
References: Journal of Experimental Zoology Part A: Ecological and Integrative Physiology
Keywords: chemical disturbance cue, bat rays, cartilaginous fish, elasmobranchs, shark behavior, marine communication, anti-predator strategy, predator-prey interactions, aquatic chemical signaling, flight response, marine ecology, behavioral study

An elusive dwarf fox that was feared extinct has been photographed for the first time, after being spotted near a highway in Cozumel, Mexico.

The tiny animal was part of the mysterious Cozumel fox population, a potentially undescribed species that had not been officially sighted in more than 20 years.

Cozumel foxes live only on Cozumel, an island near Cancún. Researchers know very little about these mysterious predators, which are roughly 20% to 40% smaller than their gray fox (Urocyon cinereoargenteus) cousins that live on the mainland.

Park and museum officials spotted and captured the fox in 2023 and, after a health assessment, released it back into the wild. Researchers have now shared the photographs and documented the encounter in a new study published May 4 in the journal Neotropical Biology and Conservation.

Although the rediscovery confirms that Cozumel foxes are still alive, they are likely on the brink of extinction, the study authors noted; the photographs highlight the need for focused research and conservation efforts.

"The biggest challenge facing the Cozumel fox is that we still know almost nothing about it, including its remaining population size, distribution, or ecology," study first author Travis Bayer, executive director of the conservation organization Pathos Wildlife, said in a statement. "That uncertainty alone is dangerous, because it makes effective conservation extremely difficult."

Cozumel foxes are an example of insular dwarfism, an evolutionary process in which larger animals, including fox-sized mammals, evolve to be smaller after colonizing islands, where there are limited resources and less space than on the mainland. The foxes aren't the only mammals that have shrunk on Cozumel over time; other examples include the island's critically endangered pygmy raccoons (Procyon pygmaeus) and dwarf coatis.

Archaeological evidence suggests that Cozumel foxes have lived on the island for at least 5,000 years, likely since before the arrival of the Maya within the past few millennia, and potentially for tens of thousands of years before that. Prior to this rediscovery, the last confirmed sighting of a Cozumel fox was in 2001, according to the study.

The rediscovery began with reports of a disoriented animal wandering near the highway on the southeastern side of the island. Officials with the Parks and Museums Foundation of Cozumel located and captured the fox, an adult male, on Sep. 14, 2023. They checked its health and later released the fox in the Laguna Colombia State Reserve, a protected area just south of where it was captured.

Recent and historical sightings suggest that Cozumel foxes could have an extremely restricted range in the island's South, where nature is increasingly threatened by development, land-use change, invasive species and natural disasters, the study authors noted.

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The researchers recommended surveys to determine the current distribution and size of the Cozumel fox population, along with morphological and genetic assessments to establish its evolutionary status and conservation efforts to protect its assumed habitat in southern Cozumel and minimize human-wildlife conflict.

"Ultimately, we hope this work helps move the Cozumel fox from a little-known, uncertain presence on the island to a better-understood key part of Cozumel's ecosystems," Bayer said. "We also hope it demonstrates that conservation is often most urgent when certainty is lowest and that uncertainty itself can be a call to action."

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When the weather gets muggy, iridescent bees shift their metallic hue, a new study finds.

The insects are a rich blue-green when the humidity is low. But as moisture levels in the air rise, their color changes: It turns a coppery green.

Many bees have a shimmery exoskeleton. So this reversible mood-ring–like effect might be quite common, scientists now say. The day-to-day color of other bees and insects might similarly change with humidity.

Jorge De La Cruz is a college student at the University of California, Santa Barbara. There, he’s training as an evolutionary biologist. He first noticed the color-change effect while preparing bee specimens for preservation and study. This was at the Cheadle Center for Biodiversity and Ecological Restoration.

Museum scientists often place insect specimens in a moist chamber. It makes them more flexible for mounting and imaging. And under moist conditions, some bees appeared to starkly shift their color. This caught De La Cruz’s attention.

“It can be a bit alarming when you’re not expecting it,” says Madeleine Ostwald. This ecologist works at Queen Mary University of London in England.

De La Cruz and Ostwald teamed up with two other researchers to look into this further. They shared what they learned April 22 in Biology Letters.

Humidity changes hue

The team studied two dozen museum bee specimens. All were fine-striped sweat bees (Agapostemon subtilior). The bees were exposed to high and low humidity for 55 hours each. After each exposure, the team took photos.

The researchers also reviewed more than 1,000 photos of living sweat bees. These came from the citizen-science app iNaturalist. Here, too, they noted the humidity present when an image had been taken. 

In dry conditions (less than 10 percent humidity), the bees were blue-green. But at 95 percent humidity, they turned a light, coppery green.

Humidity may cause layers in the bees’ exoskeletons to swell. That may change how those layers reflect light, creating an iridescence. That layering appears to scatter light at different wavelengths, creating colors. If the layers swelled, the space between them would increase. The extra space would reflect longer, redder light.

“Because we saw redder bees in more humid conditions, this fits with that [scientific explanation],” Ostwald says.

Future work with high-powered microscopes might confirm this. Lots of insects produce color with tiny structures rather than pigments, Ostwald says. So, the phenomenon might be widespread.

Color can be really changeable as something responds to the environment, she says — and “in ways we didn’t expect.” It’s important to study the color of the living organism in its natural environment to know its true hue.

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