There are times when life imitates art. Then there are times when life imitates science fiction.
One of the most famous monsters in film history is the extraterrestrial beast of the Alien series. It slowly opened its glistening fangs to reveal a second set of jaws that shot forward to kill its victims.
Scientists have now discovered a fish that does the same thing.
Rita Mehta did not have aliens in mind when she began to study the moray eel. Mehta, a postdoctoral researcher at the University of California, Davis, where she studies the evolution of feeding, was intrigued by the dining habits of morays.
They are impressively successful predators, able to devour large fish whole, and they grow to more than 3m long. Unlike other big-fish predators, morays have no fins. They hide their snakelike bodies in the crevices of coral reefs, waiting to strike. "No one knew much about their feeding behavior," Mehta said.
Morays belong to a group called ray-finned fishes that includes a vast majority of fish species, like tuna, goldfish, salmon and trout. Most ray-finned fish use suction to eat. To catch prey, they suddenly expand their mouth cavity. The negative water pressure sucks in the prey.
A second suck pulls it back to the throat. At that point, the fish typically use a set of bones, pharyngeal jaws, to pack down the food and push it back to the esophagus.
Working with Peter Wainwright, an expert on fish biomechanics at Davis, Mehta filmed morays grabbing chunks of squid. The scientists discovered that morays did not feed like typical ray-finned fish. "These fishes are not using suction to capture their prey," Mehta said. "They're strictly biting."
The strategy is not a matter of choice, Mehta found. Suction demands a set of powerful muscles and bones to change the shape of a fish's head quickly. In morays, those muscles and bones are weak and small. Mehta's findings left her puzzled. How could morays be so good at catching fish if they had no way to suck in their prey?
The answer arose as she inspected moray anatomy. She was stunned by its pharyngeal jaws. "The pharyngeal jaws look really wicked," she said.
In other fish, pharyngeal jaws are simple blocklike bones. But the morays' pharyngeal jaws looked as if they could deliver a vicious bite, despite being lodged deep in the throat. "They look like these incredible forceps," Mehta said.
It turned out that scientists published observations of the pharyngeal jaws in the 1960s, but their work was forgotten. "These were exquisite papers, and I still don't understand why no one followed up on them," Mehta said.
Forty years later, she took a closer look at the jaws and observed that the muscles that connected the jaws to other parts of the skeleton were different from those in a typical ray-finned fish. Unusually long muscles ran from the jaws to the moray eel's skull, for example.
Mehta began to wonder what would happen when those muscles contracted. "If these muscles shortened, they could pull this jaw really far forward," she said. "But then we thought, 'Oh, come on, does that really happen?'"
It does.
Mehta rigged up a high-speed video camera that could peer into the mouth of a feeding moray. "When we got the movies, we sat and stared in disbelief," Wainwright said.
The movies showed that when morays lunge for prey, they first grab it with the teeth on their front jaws. The pharyngeal jaws then shoot forward out of the eel's throat, into the mouth, and snap down on the prey.
The eel can then open its front jaws, releasing the prey, while the pharyngeal jaws move back down into the throat, dragging the food with them.
"It seems that almost everyone we showed the movie to said 'My God, it's like Alien," Wainwright said. "It really does have this monster-from-outer-space feel to it."
Mehta and Wainwright published their results in the current issue of Nature.
As strange as moray jaws may seem, Mehta sees their evolution as just a matter of tinkering with standard fish anatomy. One central step in the transition, Mehta proposes, was the loss of the front fins. The bones that once supported those fins could now take on a new role, anchoring muscles to help move the pharyngeal jaws. The other muscles that move the jaws have the same attachments found in other fish. But in the moray, some have become bigger or longer.
Shifting from suction-feeding to an alien bite may have helped turn morays into the top predators they are today. Suction works well for catching small fish, but big prey can escape the inflow of water.
To use suction, a fish has to expand its head, which can be difficult in the narrow crevices where morays often hunt.
A biting set of pharyngeal jaws, on the other hand, may have allowed morays to catch larger prey. Its front set of teeth needed only to grab onto part of an animal and hold it in place for about half a second while its pharyngeal jaws moved forward into the mouth. Now it could eat fish that were bigger than its gape.
Mehta is investigating other fishes to find clues to how the moray's double bite evolved. So far, she knows of no other animal that feeds this way. At least on this planet.
H.R. Giger, the Swiss artist who created the alien for the director Ridley Scott, was amused by the researchers' discovery.
"It's funny," he said. "The double teeth came when I did my first drawings. Ridley Scott told me to make it so that it could move. I hadn't studied any animal. My instructions were that it should be somehow frightening and horrible, and I did my best."
May 11 to May 18 The original Taichung Railway Station was long thought to have been completely razed. Opening on May 15, 1905, the one-story wooden structure soon outgrew its purpose and was replaced in 1917 by a grandiose, Western-style station. During construction on the third-generation station in 2017, workers discovered the service pit for the original station’s locomotive depot. A year later, a small wooden building on site was determined by historians to be the first stationmaster’s office, built around 1908. With these findings, the Taichung Railway Station Cultural Park now boasts that it has
The latest Formosa poll released at the end of last month shows confidence in President William Lai (賴清德) plunged 8.1 percent, while satisfaction with the Lai administration fared worse with a drop of 8.5 percent. Those lacking confidence in Lai jumped by 6 percent and dissatisfaction in his administration spiked up 6.7 percent. Confidence in Lai is still strong at 48.6 percent, compared to 43 percent lacking confidence — but this is his worst result overall since he took office. For the first time, dissatisfaction with his administration surpassed satisfaction, 47.3 to 47.1 percent. Though statistically a tie, for most
Six weeks before I embarked on a research mission in Kyoto, I was sitting alone at a bar counter in Melbourne. Next to me, a woman was bragging loudly to a friend: She, too, was heading to Kyoto, I quickly discerned. Except her trip was in four months. And she’d just pulled an all-nighter booking restaurant reservations. As I snooped on the conversation, I broke out in a sweat, panicking because I’d yet to secure a single table. Then I remembered: Eating well in Japan is absolutely not something to lose sleep over. It’s true that the best-known institutions book up faster
In February of this year the Taipei Times reported on the visit of Lienchiang County Commissioner Wang Chung-ming (王忠銘) of the Chinese Nationalist Party (KMT) and a delegation to a lantern festival in Fuzhou’s Mawei District in Fujian Province. “Today, Mawei and Matsu jointly marked the lantern festival,” Wang was quoted as saying, adding that both sides “being of one people,” is a cause for joy. Wang was passing around a common claim of officials of the People’s Republic of China (PRC) and the PRC’s allies and supporters in Taiwan — KMT and the Taiwan People’s Party — and elsewhere: Taiwan and
RSS