Stars In Their Eyes

With multiple radial arms and an admirably unhurried approach to life, you’d think that starfish had little need for eyes and simply felt their way around. Indeed, the common misconception is that starfish don’t have any form of eyes at all, however, the fascinating reality is that they actually sport several.

Starfish (more scientifically known as “Sea Stars”) have rudimentary eyes called “eyespots” which appear as tiny red or black dots at the tip of each of their arms. These microscopic eyespots are a far cry from the complex organs of mammals or fish – they are composed of simple groups of 80-200 “ocelli” that are themselves made up of pigmented cells that respond to light. Each of the ocelli is covered by a thick, transparent cuticle that acts as a protective barrier and helps to focus light. This means that despite the lack of complex structures such as a cornea or iris, they still allow the starfish to differentiate between light and darkness and detect simple movement.

While this might not seem like much, it’s actually a powerful survival tool as they help the starfish locate shade when it’s out of the water and visually navigate its environment, finding its way to shelter and food-rich environments such as coral reefs. Even simple eyes then, can help tip the balance between life and death, and indeed Scientists believe that this form of primitive eye marks an essential stage in eye evolution.