Whale sharks have layer of teeth on their eyes, new study finds
Whale sharks are the largest non-mammal vertebrate in existence, growing as long as 59 feet, or 18 meters, in length. Though endangered, they have been spotted near Eilat, but are harmless to humans.
By AARON REICHSNORKELERS SWIM with a whale shark, the world’s largest fish, at the Maldives’ South Ari Atoll in 2012(photo credit: DAVID LOH/REUTERS)
A new study has revealed that whale sharks, the largest type of shark, have eyes covered in a layer of teeth.Called dermal denticles, the teeth are small structures that may at first glance resemble scales, but are in fact composed of tiny teeth. These structures are not entirely unique – in fact, shark skin is composed entirely of dermal denticles, which help the shark swim faster in the water by reducing friction.However, their presence on the eyes is unprecedented.Rather than serving as a means of reducing friction, the teeth in fact function as a means of protecting the eyes, similar to the function of an eyelid. While many sharks do have eyelids, and some even having three, the whale shark does not, and it was believed by some scientists that the shark rotated its entire eyeball back into its socket as a means of protection. However, due to the sheer size of the sharks, it was difficult to study them.Due to new developments in caring for whale sharks in aquariums, the team of scientists from the Okinawa Churashima Research Center in Japan were able to study the shark up close and studied its eyes using new techniques such as underwater sonography and micro-computred tomography.According to the study, which was published in the online academic journal PLOS ONE, the existence of a layer of teeth on eyes is unique to whale sharks, though other prehistoric animals have had similar features, though not identical, and are now considered by many scholars to be something different entirely.As the teeth are purely for eye protection, they in no way pose a danger to humans or other animals.Whale sharks are the largest non-mammal vertebrate in existence, growing as long as 59 feet, or 18 meters, in length. Though endangered, they can be found all over the world in temperate waters. While are not found in the Mediterranean, they have on occasion been seen near Eilat and Aqaba.Interestingly, whale sharks have 300 rows of tiny teeth in their mouth, but these are used to filter feed plankton, and the sharks are in no way dangerous to human divers, and in fact have been shown to be somewhat playful. Scientists discourage this sort of interaction with them, however, in order to protect the endangered sharks.
