One of the many things that make penguins unique from other birds is that they spend time underwater and on land. They go into the ocean to hunt for food and travel; on land, they breed, raise their young, and molt. The penguin eye has several adaptations that allow penguins to see well on land and out in the ocean.

An African penguin’s eye
An African penguin’s eye

Penguins have a flattened cornea that refracts light less strongly than human or fish corneas. Their strong eye muscles change the shape of their eye lens to create a sharp, clear image both on land and in water. In addition to this, penguins have a nictitating membrane, also referred to as a third eyelid. This membrane protects their eyes from any debris that might be underwater. These visual adaptations give penguins superb vision in and out of water, and means they don’t have to wear goggles when they go out in the ocean!

Nictitating membranes can be seen slightly covering the eye of an African penguin (left) and Rockhopper penguin (right).
Nictitating membranes can be seen slightly covering the eye of an African penguin (left) and Rockhopper penguin (right).

Penguins rely heavily on visual cues for foraging, making underwater vision a must for survival. As mentioned in a previous blog about penguin taste, penguins do not rely on taste for selecting their food. Great vision on land is also necessary to identify their mate, young, nesting site, and to avoid potential predators.

So how do their eyes tell them what a yummy feast might be? It is thought that penguins, as well as many other species of birds, can see ultraviolet light (wavelengths of 320 to 400 nanometers) that humans cannot see. The way that UV light reflects off different fish may show the penguin that it is appetizing.

UV light may also reflect off penguin feathers to help penguins identify each other and assist them in mate selection. King and emperor penguin beaks reflect UV light and are thought to be a part of the mate selection process. Penguins can also identify fish by size and by smell.

No goggles required!

Stop by the Aquarium to watch our penguins swim around their 150,000-gallon saltwater exhibit! If you’re 18 or older, you can even apply to volunteer or intern in the penguin exhibit.

Conservation Context

African penguins (Spheniscus demersus) are in danger of extinction. Wild colonies along the coasts of South Africa and Namibia are threatened by the depletion of their food from overfishing, climate change, and pollution from incidents such as oil spills. The African penguin is listed as endangered on the IUCN Red List, and the species has seen a population reduction of about 90% since the beginning of the 20th century, with population trends continuing to decline.
Here at the New England Aquarium, we also do our part to help preserve the population! We participate with other organizations in the Association of Zoos and Aquariums (AZA) in a program called SSP, or Species Survival Plan. The mission of such a plan is to oversee the population management of select species to enhance conservation of this species in the wild. By breeding specific pairs, we will ensure that we have a healthy and genetically diverse population in zoos and aquariums across the country for years to come. So if you never get a chance to see African penguins in the wild, you will get a chance to see them when you visit places like the New England Aquarium.

Learn more about our African penguins: