Double bite wows scientists, according to a study published in Nature, vol 449, p79, 6 Sep 2007 and news@nature 5 Sep 2007. Biologists at the University of California, Davis have used high speed videos to study the way moray eels swallow their food. Most fish draw their food down their throat using suction method. Scientists have known that moray eels are very poor at producing a suction current, but they are voracious predators capable of eating large prey.
Some fish have extra set of plate like bones with teeth at the base of their throat that grip the food that has been sucked in and help move it into the oesophagus, the food pipe that leads to the stomach. These are called pharyngeal jaws. Rita Mehta and Peter Wainwright discovered that moray eels have pharyngeal jaws that are like long grasping arms, bearing sharp re-curved teeth. When the eel captures some prey in its front jaws the pharyngeal jaws are pulled forward to grasp the prey and pull back carrying the prey down the eel’s throat using a ratchet mechanism similar to the way snake force their prey down their throat.
The researchers commented to news@nature that there is a “remarkable similarity between eels and snakes, despite the fact that they are from completely different realms of the animal kingdom.” Mark Westneat of the Field Museum of Natural History, Chicago, commented that the discovery of the eel’s double bite harks back to an age when scientists discovered natural phenomena, rather than developing theories and testing them. He said it was “a classic example of discovery-based science, stemming from a ‘wow’ moment”.
Editorial Comment: Westneat’s comment about how science works in the practical day to day world challenges the commonly made claim that you cannot do science without the theory of evolution. In reality, science is carried out by people who simply observe things happening in the world around them and then take a closer look to see what else they can find out. The theory of evolution is usually applied to the findings afterwards, and makes no difference to what was actually found.
When an animal is found to have an efficient method of biting or grasping food it is usually claimed that it evolved to be a voracious killer. However, an animal’s jaws and teeth only determine how it eats, not what it eats. Therefore, finding an animal with an impressive double bite does not mean it was created to be a killer. The double jaws would be useful for gripping and swallowing any kind of food. (Ref. diet, fish, methods)
Evidence News 23 April 2008