Environment

The Best Adaptations Animals Have Developed To Living In The Darkness

There is more than one adaptation to "seeing" in the dark than just night vision!

There are many reasons why animals need to adapt to the darkness: either it is an innate characteristic of their environment (deep sea, caves). Alternatively, it can be an evolutionary development to make hunting more efficient, or to avoid competition for resources or dangers of the daylight. There is more than one adaptation to "seeing" in the dark than just night vision!

Vibration Sensitivity

Vibration from the movement can travel through the water and sand, and Grant's golden mole living in Namib desert utilizes that. This creature cannot hunt during the day, as it is too hot, and the sands tend to collapse, so they cannot build reliable tunnels to scavenge in. There is also no leaf layer rich in insects and grubs. 

This unique animal had to adapt to foraging in the dark. At night, they roam their territory, periodically dipping their heads into the sand to detect the low-frequency vibrations. They are so sensitive that they are able to detect even the signals from the movement of their favorite food - termites.

Percussion And Hearing

Since sound waves remain unaffected even at night, it is only logical that many nocturnal animals evolved to utilize them. Where bats use ultrasound sent through the air, the aye-aye, a Madagascar lemur, uses percussion to detect food inside the wood. These odd-looking creatures have a highly specialized set of tools - their six fingers, a sensitive hearing, and rodent-like teeth to open the wood up.

The fingers are definitely the aye-aye signature feature. To begin with, they have 6 of them: the sixth digit, called pseudothumb, aids in gripping. The third finger, thin and sturdy, is used for rapid tapping on the wood. The fourth finger - the longest and with a hooked nail - is used to extract grubs from the burrow. 

The night hunt of the aye-aye looks like this: the travel the tree canopy, rapidly tapping on the trunks and branches. Then they listened to the reflected sound waves (echo) to detect cavities that might signify a grub burrow. When they find a promising one, they use their ever-growing sharp teeth to open the hole, stick their longest finger there and pull out the food. 

Echolocation

Humans and most animals use the reflection of the light to see the surroundings. However, sound waves can be used for "seeing" the same way. Echos are sounds waves reflected from the objects in its pass, and some animals evolved to replace the light with them. They detect the return echoes and use it to navigate in the environment with little to no light with precision.

Most well known nocturnal animals that use echolocation are bats. Unlike those animals that rely on the reflection of the light waves produced by some other sources, they have to send out their own waves: bats emit high-pitch cries, receive the returning echo, and process it to "see" the environment and food. By sending repeated sound impulses, bats can see the world in dynamic. Their ears and brains have special adaptations for processing echolocation, and they can see even tiny insects the way animals which rely on the light see them with eyes. 

Infrared Vision

Although many snakes are active during the day, there are some that adapted to hunting at night. Instead of enhancing their light sensitivity, they evolved to rely on infrared vision (infrared waves are the heat waves invisible to the human eye because they are outside of our vision spectrum). 

This can only be considered vision in the sense that it allows them to map the environment and to detect prey: technically, they have proteins that are extremely sensitive to the heat waves emitted from the bodies of the living creatures. Pit viper snake family, which includes pythons, boas, and rattlesnakes, got its name from the "pits" on the forward-directed parts of their jaws lines with the heat-sensitive elements. 

Enhanced Light Sensitivity

Many nocturnal animals adapted to the darkness by improving their night vision. Their pupils dilate much more than the human eye's ones. Many have a special reflective lining - the tapetum lucidum - in the eye that allows recapturing even the faintest light. This reflective lining is what causes the familiar eyeshine of the cats, owls, and other nocturnal animals. 

Tarsiers are one of the extreme examples: these small mammals have eyes that are larger than their brains. It allows them to find even tiniest insects in almost complete darkness. In most cases, these animals traded the enhances low-light vision for the color sensitivity: many of them are color-blind. 

How can bats ''see'' the world?

By sending repeated sound impulses, bats can see the world in dynamic. Their ears and brains have special adaptations for processing echolocation, and they can see even tiny insects the way animals which rely on the light see them with eyes. 

Citations

Your MLA Citation

Your APA Citation

Your Chicago Citation

Your Harvard Citation

Remember to italicize the title of this article in your Harvard citation.

More in Environment