Which animals have cones

Owls are much smaller than humans, but our eyes are nearly the same size. The results are great—if you put an owl on a soccer field lit by a single candle, with no other illumination from the moon or stars, the owl would probably be able to see a mouse anywhere on the field. In order to see from side to side, the owl has to turn its head. To compensate, owls can turn their heads almost completely around, granting them a wide vision field.

The tarsier is a tiny primate in Southeast Asia. The little animals are only about four inches long, excluding their tails. However, their eyes are about half an inch wide, which means their eyes take up nearly their entire head. Tarsiers have the biggest eye-to-body-size ratio known in the animal kingdom. Tarsiers are nocturnal predators, looking for insects and small lizards or birds when there is little to no light available. They have to be able to spot and stalk prey in the treetops, jumping from branch to branch in the dark, and their prey is tiny and often camouflaged.

Other animals can see well in the dark in different ways. Snakes, for example, rely less on rods in their retinas and more on thermal vision, which lets them see the body heat of nearby mammals. Also, their pupils function much as the aperture for a camera does, dilating significantly when they need to take in extra light.

Cats in particular have exceptionally large pupils for their body size and outstanding night-time vision. Like all animals, some light is required for the eye to function properly. The only animal that has been confirmed to see only in black and white is a fish called a Skate.

This is because it has no cones in its eyes. Skip to main content. Veterinary care now, pay later! Animals only see in black and white. Pet type s :. Pet library topic s :. In humans, there are three types of cone cell that are responsible for the early stages of colour vision.

Each type of cone cell is maximally absorbent in a different part of the spectrum — short, medium and long wavelengths of light. When light hits the eye, the cones are stimulated differentially according to their type, and the relative excitation of each type underlies colour sensations. In a process known as colour opponency , the outputs are then compared against each other in various permutations.

This information is then sent to and interpreted by the brain, which provides the final sensation of colour. Animals vary in the number and sensitivity of cones present, so visual processing can result in very different colour sensations, even before differences in brain processing are taken into account. Most mammals are dichromatic — they have only two cone types blue and green sensitive.

Humans have three types of interacting cones and so are trichromatic, although there is at least one documented case of a female having four cones. Apes and Old World monkeys also have trichromatic vision, but New World monkeys have variable colour vision that is also sex-linked, meaning that males and females of the same species can have different numbers of cone type. Generally, females are trichromats whereas males are dichromats as they lack the photoreceptor that is sensitive to red wavelengths of light.

In several species of New World monkey, such as marmosets and tamarins, all males are dichromatic but females may be either dichromatic or trichromatic. Trichromacy may offer a foraging advantage by enabling green and red food items to be easily distinguished, but may also be useful in signalling amongst individuals of the same species, whereas dichromacy may be advantageous when foraging for camouflaged food or in low light levels.

Bees are also trichromatic, but they can see ultraviolet UV light as they have a UV sensitive receptor, as well as blue and green sensitive receptors.