Chameleon eyes

Amazing eyes: 17 vision champions

From eyes the size of a dinner plate to 360-degree vision, these animals boast extraordinarily efficient ways of seeing.

Meet the creatures with the most crafty, strange and sophisticated eyes in the animal kingdom.

A tarsier

Tarsiers' eyes are large but they don't move - meaning the primates must swivel their heads to scan their environment © Bambara/Shutterstock.com

 

1. Tarsiers (Tarsiidae)

These small primates have the largest eyes of any mammal, relative to their body size. Each eye is about the same volume as the animal's brain.

Trilobite eyes

An ancient tower-eyed trilobite with dozens of calcite lenses. Trilobites evolved a wide variety of eye forms.

 

2. Trilobites (Trilobita)

Trilobites lived between 521 and 252 million years ago. They were one of the first groups of creatures to develop complex, compound eyes, where many individual lenses focus light onto groups of photoreceptor cells. 

This group of hard-shelled prehistoric creatures had crystal lenses made of calcite, which helped them see very clearly - even in dark ocean water.

Dragonfly eyes

Dragonflies have very large eyes relative to their body size. They almost cover their whole head. © Kurt G/Shutterstock.com

 

3. Dragonflies (Anisoptera)

Some species of dragonfly have more than 28,000 lenses per compound eye, a greater number than any other living creature.

And with eyes covering almost their entire head, they have nearly 360-degree vision too.

Gecko

Even in dim light geckos can see colour exceptionally well © Fivespots/Shutterstock.com

 

4. Geckos (Gekkota)

Nocturnal geckos have superb vision in dim light - their eyes are 350 times more sensitive to colour at night than a human's (see for yourself with our animal vision interactive).

Lacking eyelids, they use their tongue to keep the eye clean.

Colossal squid eye

Colossal squid eyes can grow to at least 27 centimetres in diameter © Natalie Jean/Shutterstock.com

 

5. Colossal squid (Mesonychoteuthis hamiltoni)

Researchers believe the collosal squid's eyes are the largest of any living creature, measuring over 27 centimetres in diameter - the size of a football.

Reindeer eyes

Reindeer eyes change colour with the seasons © Arildina/Shutterstock.com

 

6. Reindeer (Rangifer tarandus)

The eyes of Arctic reindeer change colour with the seasons, from gold in the summer to blue in the winter. The technique allows them to make the most of changing light levels in their extreme habitat.

Four-eyed fish

Specially adapted eyes allow the four-eyed fish to see above and below the water at the same time © KayVee INC, licensed under CC BY-NC 2.0

 

7. Four-eyed fish (Anableps anableps)

Able to see above and below the water line at the same time, the four-eyed fish has eyes that are split in half horizontally.

Each half has its own pupil and retina (the light-sensitive layer of tissue), allowing them to function separately.

Gigantocypris

The two large eyes of Gigantocypris, a deep-sea crustacean, provide it with the best night vision of any living animal © Martin Angel, licensed under CC BY-NC-SA 4.0

 

8. Gigantocypris

Living in the deep sea, these ostracods (a kind of crustacean) never see sunlight. They have the best night vision of any known animal and probably use their eyes to search for bioluminescent animals to prey on.

Gigantocypris has a pair of concave mirrors in each eye, rather than a lens, to focus light onto its photoreceptors.

Acanthodes bridgei

The first evidence of colour vision was found in a fossil of the extinct spiny shark Acanthodes bridgei © Gengo Tanaka et al, licensed under CC BY 4.0

 

9. Acanthodes bridgei 

A 300-million-year-old fossil of this extinct fish provides us with the oldest direct evidence of colour vision.

The fish's retina has rods and cones, the photoreceptor cells that allow living vertebrates to see in colour. Rods are light-sensitive cells, and cones are sensitive to colour.

Ostrich eye

Ostriches have the largest eyes of any living land animal © Macarena Viza, licensed under CC BY-NC-ND 2.0

 

10. Ostrich (Struthio camelus)

An ostrich's eye is bigger than its brain, and is the largest eye of any living land animal, measuring five centimetres across.

Cock-eyed squid

The cock-eyed squid uses two distinctively different eyes to scan its environment © L. Madin/NOAA/Census of Marine Life, via Wikimedia Commons

 

11. Cock-eyed squid (Histioteuthis species)

These squid have one small, blue eye and one large and yellow, bulging one, creating a bizarre silhouette.

Scientists think the larger eye scans the water above the squid for prey silhouetted against the light, and the smaller eye searches the murky depths below.

Chameleon

Chameleons have nearly 360-degree vision © Pat O'Malley, licensed under CC BY-NC-ND 2.0

 

12. Chameleon (Chamaeleonidae)

Chameleons have some of the strangest eyes on the planet, which are able to move independently of each other. This results in almost 360-degree vision.

The reptile can also switch between monocular vision - when both eyes are used separately - and binocular vision, when both eyes are used to look at the same scene.

Purple sea urchin

Sea urchins have light-receptor cells all over their bodies © NatalieJean/Shutterstock.com

 

13. California purple sea urchin (Strongylocentrotus purpuratus)

The California purple sea urchin is so packed with photoreceptors on its surface that its body has been described as a single functional eye.

Because nearly the entire sea urchin is sensitive to light, it can 'see' in every direction. Researchers have suggested the sea urchin uses its spines to block out some of the light hitting it, to help focus the light for better vision.

Mantis shrimp

Mantis shrimps can process both polarised and ultraviolet light © Teguh Tirtaputra/Shutterstock.com

 

14. Mantis shrimps (Stomatopoda)

Mantis shrimps probably have the most sophisticated vision in the animal kingdom. Their compound eyes move independently and they have 12 to 16 visual pigments compared to our three.

They are the only animals known to be able to see circular polarised light. Experiments suggest they may use this to send messages to each other - for instance, 'this burrow is occupied'.

Camel eyes

Keeping dust away from the eyeball is a priority for camels © Seleznev Oleg/Shutterstock.com

 

15. Camel

Camels have eyes that are specially adapted to their hot, dry surroundings.

Two eyelids with very long lashes keep sand from blowing into a camel's eyes. A third eyelid sweeps across from the corner of the eye to help clean the surface.

Male striped horsefly

The huge eyes of male striped horseflies have two types of photoreceptor units © Thomas Shahan licensed under CC BY 2.0

 

16. Male striped horsefly (Tabanus lineola)

As well as having massive eyeballs that join at the top of the head, these horsefly males have two different sized ommatidia (the photoreceptor units that form insects' compound eyes).

The larger ommatidia at the top of the eye are more sensitive to UV light, and help him spot the fast-flying female flies, while the smaller ommatidia help him hone in on details.

Read more about the interesting eyes of these much maligned flies in our Curator of Diptera blog.

Cyanobacteria

Blue-green bacteria, called cyanobacteria, use photosynthesis to obtain their energy from sunlight

 

17. Bacterial cells

Bacteria aren't actually animals - they're single-celled microbes. But they deserve a mention because they are probably the world's smallest and oldest example of a camera-type eye. Camera-type eyes use a single lens to focus light onto a sensitive membrane or retina.

Recent research has shown that the tiny cells of some cyanobacteria (bacteria that get their energy from sunlight) act like a lens. Their spherical body bends incoming light rays, focusing them on the opposite surface. Their entire body effectively becomes an eyeball.

A bacterial cell can sense the direction the light is coming from, and move towards it.