Alien Jaws Enable Elite Predator



What has poor eyesight, a keen sense of smell and Alien jaws? You may find them hiding in a crevice, beneath a section of a wreck or out on a nocturnal hunt. Moray eels: There is more to these fascinating creatures than meets the eye. In fact, you actually need some X-ray vision to get a closer look at their intriguing feeding habits.

Your average fish predation involves suction. When a fish finds a tasty treat, it expands its oral cavity, sucks in water and the food with it. Other types of fish predation involve grabbing the prey with the jaws and using suction to transport the food into the esophagus. But researchers at the University of California Davis (UCD) found that moray eels are not your average fish.

Using a high-speed digital camera to film eels feeding in the UCD laboratory, Dr. Rita Mehta, assistant professor of ecology and evolutionary biology at the University of California Santa Cruz (UCSC), captured a shocking image. She discovered that when the moray eel has its prey in its powerful grasp, muscles in the moray's throat thrust forth a second pair of jaws from behind the eel's skull, which grabs the food and carries it back into the esophagus to be swallowed and digested. The high-speed film was able to capture a glimpse of the rapid movements of these secondary pharyngeal jaws. Mehta further examined these feeding habits using X-ray imaging equipment and conducting anatomical dissections.

While many species of fish have pharyngeal jaws, they are typically utilized for grinding or crushing prey. The function of the pharyngeal jaws in moray eels is strikingly unique; it has yet to be observed in another species. "Without the dependence on suction feeding and a mechanical way of swallowing prey, morays can feed out of water as well as in the water," Mehta said. "This mode of transport is analogous to ratcheting behavior in snakes, a clade of vertebrates that have independent movement of their left and right jaws and have converged on a similar body plan." In other words, this unique function makes the eel an elite marine predator, enabling it to reach and devour prey in tight sections of the reef where suction methods would be prohibitive.



Mehta and her team continue to delve into the mysteries of the moray eel at the Mehta Lab at UCSC, also known as the ELVer Lab, where they study elongate limbless vertebrates from both an evolutionary and ecological perspective. "We are in our third year of funding to explore the diversity of morays and to better understand their pharyngeal jaws," said Mehta. "In collaboration with researchers at UC Davis and UCLA, we are currently examining the evolution of different trophic regimes in morays that have led to their underlying skull diversity."

As their investigations continue, who knows what other sci-fi quality secrets they'll uncover?

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