Scientists have discovered that the world’s largest sharks have tiny teeth on their eyeballs.
In a study published in the journal PLOS One, researchers at the Okinawa Churashima Research Center in Japan, led by Taketeru Tomita, found small teeth on the eyes of a whale shark, an easy animal noticed with a unique speckled skin layer.
Whale sharks have eyeballs that protrude from their sockets, a trait that makes them more vulnerable to injury. They do not have eyelids, and the only known defense mechanism is that this species can rotate “the whole eyeball in the orbit”.
Due to the limited number of individuals, it is difficult to use traditional methods to study large ocean creatures such as whale sharks. In the latest study, the team used samples of whale sharks kept in the aquarium, as well as dead specimens. They used a variety of techniques to examine the morphology of their eye protection and compare them with other sharks. The results show that whale sharks have unique “armored eyes”.
The whale shark’s toothed eyeball is a new eye protection in vertebrates, the team said. According to these scientists, “the teeth appearing in the contour of the eyes morphologically different from the teeth appearing on the skin are distributed over the rest of the body”.
“To our knowledge, eye teeth have not been found in the shark subclass (sharks and rays), including those closely related to whale sharks,” the researchers admitted.
The study points out: “The teeth in the eye are a unique feature of whale sharks.” Their results also showed that the eyeballs of whale sharks can rotate and retract, giving them additional protective capabilities.
In the past, it was believed that whale sharks relied almost entirely on sight compared to other senses. However, recent findings reveal other aspects. The above scientists suggest that future research should focus on other aspects of vision, including color gamut, field of vision, and sensitivity.
