L’ELIXIR DE MORAY

GEE, LYRICAL EEL talk is fun! It started with a memorable headline in Sabrina Imbler’s Trilobites science article in The New York Times, June 22, 2021: It’s titled “When an Eel Climbs a Ramp to Eat Squid From a Clamp, That’s a Moray.”

“In the video,” Imbler reports, “forceps nudge a piece of squid that sits on a ramp as an offering. Suddenly, a snowflake moray eel named Qani heaves its muscled bucatini of a body out of the water and onto the ramp. It opens its mouth and bites the squid. The eel pauses a moment, opens its mouth again and, as if its tongue were a conveyor belt, sucks the squid even deeper into its mouth using a secret second set of jaws in its throat.”

Significant Findings. There are two confirmations inherent in this feeding episode: The moray, normally an aquatic animal, came onto land to eat. And its second set of jaws gives the moray a distinctly different gustatory behavior than that of other fish.

These and other findings come from a six-year study undertaken by Dr. Rita S. Mehta and colleagues at the University of California, Santa Cruz. Full details are given in “Snowflake Morays, Echidna nebulosa, Exhibit Similar Feeding Kinematics in Terrestrial and Aquatic Treatments,” by Rita S. Mehta and Kyle R. Donohoe, Journal of Experimental Biology, Volume 224, Issue 11, June 2021. 

Though its title may offer less flash than that of The New York Times, the paper gives fascinating insight into the rigors of science. The researchers note, “Through the process of positive reinforcement and shaping (rewarding the individual for incremental progress towards the desired behavior), fish learned to feed on the ramp or platform without retreating to the water.”

Not Your Typical Fish. Most fish eat by sucking water and prey into their mouths. However, morays have evolved beyond this “suction feeding.” 

Morays grasp their prey with a formidable set of teeth, then swallow it using a pharyngeal jaw, a second set of teeth located in the pharynx.

Fish Desiccate on Land. Imbler notes, “Like many other fish, morays will eventually dry out if they leave water for too long. But Dr. Mehta and her colleagues cite a study from 1979 that suggests a moray’s outermost layer of skin contains certain mucus glands that may make these eels more resilient to time spent on land.”

Getting to Know Morays. During the six-year study, researchers got to know a succession of snowflake moray subjects. Qani, for example, was a quick study: Imbler observes that researcher Donohoe (who once trained seals and sea lions) “trained Qani to wiggle farther and farther up the ramp and feed from forceps in just three weeks—the fastest of any eel in the study.”

Benjen, a snowflake getting its moniker from the Affleck Lopez relationship, was nearly 21 in. long, twice Qani’s length. Imbler notes, “The mammoth moray would ascend the ramp only for chunks of squid so large and disproportionate to the eel’s body that one of the paper’s reviewers requested Benjen be stricken from the statistical analysis of the paper.”

“ ‘But he’s the star of the lab,’ Dr. Mehta said.”

My Brief Moray Encounters. When I lived on St. Thomas, skin-diving I’d occasionally see morays peering out of grottos of coral. Scary, though I suspect they were probably just breathing, not being aggressive.

As another example, barracudas had an unnerving attraction to shiny things, like a diver’s mask hardware. They’ve also been known to disappear from one place and instantly reappear in another.

I envy the UC Santa Cruz researchers’ opportunity to get to know these sea creatures better. I love the Benjen tale, even though it didn’t make the final paper. ds

© Dennis Simanaitis, SimanaitisSays.com, 2021