Dive Dry with Dr. Bill

#228: Tyrannosarus Morayensis!

I'm sure many of you have had the pleasure of wandering through a real museum of natural history, either as kids or as a parent taking your own children. Growing up in Chicago, the Field Museum of Natural History was (and still is) a favorite place for me to visit. However, it could just as well be the Los Angeles County Museum of Natural History for those who grew up in this region. Children are often fascinated by dinosaurs, and the bravest among them may gravitate towards the skeletons of the huge plant-eating Apatosaurus excelsus (formerly Brontosaurus) or the vicious predatory Tyrannosaurus rex known in my youth, and in Steven Spielberg's "Jurassic Park," as a T. rex.

Fortunately, as far as we know, the marine world has no equivalent of these giants since the ancient ichthyosaurs are all extinct (right?). The blue whale, bigger than both the Apatosaurus and T. rex, munches on plankton rather than vertebrate flesh like ours. The huge Megalodon ancestors of the great white sharks have (hopefully) disappeared from our waters. Sure, their smaller relatives could take a chunk out of us, but that is a very rare event and not something I'd spend much time worrying about. However, a few years ago while walking the beaches of a remote island in the Gulf of California (or Sea of Cortez to those who don't realize the murderous impact of Hernando Cortez on the ancient Aztec civilization), I discovered a rather dimunitive skull reminiscent of the T. rex on my childhood visits to Chicago's museum.

You have probably already guessed that the skull I found came from a marine fish known throughout the world as a moray or murree eel. Yes, it looks as vicious as any T. rex... but the jaws on this one were a mere 2 1/2 inches long. A living specimen with jaws twice that size might be able to clamp down on my forearm if I were careless enough to place it where the poor eyesight of this fish might confuse it with something tasty. Certainly there are tales of divers who have reached into dark holes for a lobster, and had a moray give them quite a surprise... occasionally a very painful one. However, as long as a diver exercises reasonable caution, it is unlikely they will suffer during an encounter. There were no morays in the freshwater I dived in my early years, but in 38 years of on-again, off-again diving here and around the world, I've never had a problem with a moray.

Recently a video of a moray "attack" has been making the rounds on You Tube and ScubaBoard. It was reportedly filmed in Thailand, and shows a dive master feeding a moray... hotdogs. Now feeding a wild animal a food which is barely fit for human consumption (thanks to the nitrates and other preservatives in it) is something to be discouraged. It reminds me of those who have fed our island foxes Wheat Thins or pieces of chocolate... definite no no's. The I.Q. of this dive master must have approached that of a stone (a sedimentary one at that). What person possessed of a functioning brain would feed a very toothy animal something that looks just like their finger? Remember, a moray's eyesight is not very good, so even if you can differentiate between the two, the moray probably can't. Yep, you guessed it. According to the video, the moray bit off one of the dive master's fingers! Now some think the video is just a hoax, but I wouldn't put it past a mentally challenged dive master and a near-sighted moray.

Looking at the moray's skull in the accompanying picture, it is fairly obvious that the jaws possess many sharp teeth. Morays with dentition like that are obviously piscivorous or "fish eating." The sharp teeth grab and firmly grip the slithering fish as it begins its journey down the moray's digestive tract. No U-turns allowed once they bite down. Our California morays, the only species in our waters, generally feed at night when they come out of their daytime shelters. Noted fish biologist Dan Gotshall says they feed on crabs, lobster and sea urchins in addition to fish, but based on my observations they seem to prefer the numerous blacksmith in our waters. Our California species has southern affinities and is found from Pt. Conception to Magdalena Bay, Baja California, Mexico, where the gray whales calve and winter.

While preparing my latest underwater DVD on the common fish and invertebrates of the Gulf of California, I had to do some research to identify one of the morays I filmed at a beautiful little islet known as Los Islotes. I had already identified the common ones I filmed like the Panamic green, slenderjaw, tiger reef and jewel moray. Initially this one eluded assignment to a species until I did a bit of Internet research and discovered it was a snowflake moray. One thing that helped me identify it was the teeth. They were not as sharp, and looked as if they might be more suited to crushing instead of grasping and tearing. I discovered that the snowflake moray is one that generally does not eat fish. It prefers to munch on crab and shrimp.

So you can tell a lot about the diet of a critter by looking at its dentition. I remember my family dentist telling me years ago that I didn't need the sharp fangs, or eye-teeth, in my mouth unless I planned to wander around on nights of the full moon and penetrate the necks of unsuspecting "young" (at least in their 20's) lovelies. Of course that was precisely my plan, but I couldn't tell Dr. Don that! He took a grinding wheel and tried to file down the sharp tips of those fangs... until his drill broke! Fortunately I have them to this day and can indulge in a varied diet of type-O blood once a month in addition to the occasional flank steak, salmon, crab, shrimp, or fruits and vegetables. I simply choose which of my many teeth I use as the implements of destruction. Don't worry ladies, you are out of danger... the full moon was on April 2nd (a lucky day for Esther). Of course my dive buddies have little to fear. I don't do many night dives in our chilly waters, and I'd have a hard time biting down on their necks underwater due to the regulator in my mouth (breathing does take precedence over munching). However, there is always the surface interval! Aaaaaoooooohhh! Werewolf of Avalon.

© 2007 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," "Belize It or Not: Western Caribbean Invertebrates, Fish and Turtles," "Gentle Giants: Giant Sea Bass" or "Common Fish and Invertebrates of the Sea of Cortez" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!

Skull of the moray eel found in the Gulf of California.

This document maintained by Dr. Bill Bushing.
Material and images © 2006 Star Thrower Educational Multimedia