Friday, May 15, 2009

WOW: All About Eels!

By Adele Fowler, World of Water Aquarist

Welcome back to the World of Water! Let’s head over to the Gulf Tank and answer a few questions about one of our most interesting animals: Buddy the eel! Buddy, a green moray eel, may look vicious and intimidating, but it is mostly just for show. He’s actually very tame, and loves having his back scratched!

Moray eels are remarkable animals and are not as dangerous as many people believe. In fact, in ancient times, eels were held in high regard. Julius Caesar once had six thousand morays on display at a party! Wealthy politicians used to decorate their pet eels with jewels. Their savage reputation may very likely come from one particular legend of a wealthy Roman who used to feed disobedient employees to his pet moray eels. In the present day, there have been very few instances where divers have been bitten, and in those cases, it was an accidental bite from human-initiated interaction. Morays are very shy and secretive, and would much rather flee than fight.

Another common misunderstanding is that the moray eel’s bite is poisonous. While they are not poisonous, morays can inflict a nasty bite, since their sharp teeth are covered with bacteria that may infect the wound. The only way that we could be poisoned by a moray eel is if we ate one. Eels, along with certain fish, can cause a bacterial infection known as ciguatera poisoning. Remember, Buddy doesn’t want to eat you and you don’t want to eat Buddy!

Moray eels are fish, and are found in the family Muraenidae, which is the family of “true eels.” There are 200 species in this family, and the average length of a moray eel is around five feet. The largest moray eel (the Giant Moray) can reach a length of up to 10 feet and weigh over 80 pounds! They are found in all tropical seas, and live in crevices in reefs, where they lie in wait for their prey, which consist of animals such as other fish, squid, octopuses, clams, and crustaceans. Their jaws and teeth are even specially adapted to eat these types of animals.

Moray eels have long, thin teeth, and the larger teeth are hinged to permit the smooth passage of prey into the stomach. The teeth also point backwards, so that when a moray catches its prey, it makes it more difficult for the animal to escape. They even have a SECOND set of jaws in the throat to aid in swallowing prey! These are known as pharyngeal jaws, and morays are the only type of animal that use them to actively capture and restrain prey. When feeding, morays launch these jaws into the mouth, where they are able to grab struggling prey and transport it into the throat and down to the rest of the digestive system. Eels are known as ambush predators- instead of actively searching for their prey, they lie in wait until a potential food item comes along, and then attack. Since eels can not see or hear very well, they rely mainly on their highly developed sense of smell to detect prey.

Our eel, Buddy, is almost 6 feet long and weighs about 65 pounds. We estimate him to be about 12 years old. Buddy may appear green, but believe or not, his skin is actually blue! Eels secrete a thick mucus over their skin, and the color of the mucus that is secreted over Buddy’s skin is yellow. And since yellow and blue mixed together make the color green, this is what gives Buddy his color! Buddy is nocturnal, meaning that he is most active at night, so you can normally find him napping during the day in the tank. The only time he will really come out during the day is at feeding time –he is trained to hand feed at the top of the tank. And everything that Buddy eats is carefully recorded.

If you have visited Buddy in the World of Water, something that you may have noticed is that he constantly opens and closes his mouth. While it may seem that he is being aggressive, it is actually his way of breathing! When he opens his mouth, he is actually passing water (and oxygen) over his gills. The water exits through two vent-like openings at the back of the head.

Next time you visit the World of Water, take a look at the Gulf Tank and try to spot Buddy. He is fed on Monday, Wednesday and Friday around 1:30, so come by and watch! The World of Water’s next blog, in honor of the new Shark and Ray Touch Tank, will be all about stingrays!

Contributor Profile:
Loretta and Adele's backgrounds are in the life sciences. They both love their jobs as well as all animals. Adele grew up here in Birmingham and is into yoga and gourmet cooking. Loretta grew up in Florida and just had her first child!

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