With the onset of autumn, the days become shorter, and it gets dark outside quite early. Because of this, people are forced to illuminate everything around them so as not to stop their daily lives. However, in parallel with us live thousands of creatures who can see perfectly in the dark. Early sunset becomes an additional advantage for them, allowing them to carry out many mandatory daily tasks. Such abilities of animals interested people, which gradually led to the appearance of night vision devices. They became a revolutionary discovery that is actively used in our time.

The process of emergence of night vision in animals

Animals are unique creatures of nature. They exceed human capabilities by many criteria and often amaze us with their abilities. However, this was only sometimes the case. The first mammals appeared about 200 million years ago and were primitive animals that more closely resembled modified reptiles. They gradually evolved into the living creatures we know today.

In parallel with the living creatures of that era, their abilities also evolved. Some of them disappeared due to uselessness, while others became more pronounced. So, one of the main features of some mammals, reptiles, birds, and insects was the ability to see at night. According to scientists' research, the photoreceptors that provide such vision developed in animals that lived during the Jurassic period. At this time, they shared their home with dinosaurs, which had a significant size, weight, and strength advantage. These creatures were active exclusively during the day, so other living animals had to switch to a nocturnal lifestyle. Otherwise, they would have been eaten by their insatiable neighbors.

The desire to avoid direct contact with dinosaurs led to many animals of that time adapting to life at night. After the disappearance of the giant reptiles, some species returned to their origins and began to emerge from hiding during the day. At the same time, thanks to evolutionary processes, night vision remained in some of these animals. They did not lose their skill even after millennia, so today, we can observe many fauna that can be seen at night.

When considering evolutionary processes from a scientific point of view, it is correct to rely on researchers' conclusions. They all found that night vision evolved in animals, creating an imbalance between the rods and cones (cylindrical and conical photoreceptors). The dominance of rods led to the fact that some living creatures that inhabited our planet learned to see in minimal light. This difference increased so much in some species that they could no longer see usually in sunlight. Subsequently, these animals completely switched to a nocturnal lifestyle and have retained this feature.

Features of night vision of animals

Despite the external similarity, the organs of vision of animals have little in common with human ones. The same significant difference is observed in the principles of their functioning. Our eyes collect light rays using the pupil. Next, they fall on the lens, which focuses on the image, preparing it for further processing. Then, the retina comes into play. With increased sensitivity to light and cylindrical and conical photoreceptors, its cells process information and send it to the brain. There are four times more rods in the retina, which provide daytime vision, than cones. That is why a person can usually see only in the sun's light or some lighting device.

In animals, the situation is slightly different. In their organs of vision, rods, and cones are imbalanced compared to humans. This difference is relatively small in species that are equally active during daylight and darkness. Thanks to this, such animals can see usually day and night. A striking example of such a living creatures is the cat. She sees well in a minimum of light but leads a predominantly diurnal lifestyle. In some species, the difference in the number of rods and cones is absent or leans towards the latter. We classify these species as those that are nocturnal.

Returning to cats (the animals closest to us), it should be noted that their visual system is built differently than humans. These mammals have relatively large eyes and huge pupils. The latter are three times larger in diameter than human ones. However, this is observed only in the absence of standard lighting, when maximally dilated pupils help cats capture the maximum available light, creating a brighter and clearer image for the animal. Another feature of cats and some other species is the presence of an additional layer of cells in the organs of vision. It has a unique ability to reflect light, which makes it possible to maximize the sensitivity of the organs of sight and improve visibility. This layer of cells reflects light rays and causes a cat's eyes to glow red or green at night).

Popular animals with night vision

There are tens of thousands of animal species living on our planet, but only a few can see at night. These representatives of the fauna are often nocturnal or combined with activity during daylight hours. Each animal has its characteristics of night vision, which need to be discussed in more detail.

Popular species with night vision:

1. Cats. Famous representatives of the animal world that can see at night are cats. All their varieties are distinguished by excellent vision, which helps them perform any task. Domestic cats do not use their skill as often as wild cats. Therefore, their night vision could be more developed. Tigers, lions, and other cat relatives also can see in the dark. It allows them to hunt vacationers and unsuspecting mammals. This dramatically increases the chance of success and increases the likelihood of their survival in the wild.
2. Wolf. These natural-born killers are at the top of the food chain. They see equally well at any time of the day and have an excellent sense of smell. Wolves have huge eyes, thanks to which they collect maximum light. Their retinas contain approximately the same number of rods and cones. 
3. Moreover, the number of one and the other is much greater than that of a person. Thanks to this, wolves can distinguish nearby objects even in the dark. What they lack in long-range vision, they compensate for with their excellent sense of smell, capable of picking up the scent of a potential victim from a very long distance.
4. Fox. These intelligent and agile mammals live on all continents. They are predominantly nocturnal, so they need the ability to see well without standard lighting. This ability is perfectly developed in foxes. They quickly notice prey in low light conditions, leaving no chance of escape. The structure of foxes' visual organs is such that they can see well at night and during the day. This became possible due to the increased percentage of rods and cones in the retina. Like wolves, foxes have an excellent sense of smell, compensating for minor visual deficiencies.
5. Hedgehog. This small mammal has poor daytime vision but can see well at night. This is due to the unique structure of their eyes. These organs in hedgehogs are tiny, but in terms of sensitivity to light, they are ahead of most mammalian eyes. Thanks to this, hedgehogs can see perfectly, even in minimal lighting. They use their skills to search for prey. They often become small invertebrates, insects, and other representatives of fauna.
6. Owl. These birds have the most perfect eyes. Their visual organs are a real work of art. The main feature of this bird's eyes is their ability to adapt to current lighting conditions instantly. This occurs due to the narrowing and expansion of huge pupils. There are legends that owls cannot see anything during daylight hours. This is false since they can distinguish objects even in very bright sunlight. However, these birds are nocturnal inhabitants and hunt mainly after sunset. At this time, their vision sharpens significantly and becomes hundreds of times better than a person's. Even on a cloudy night, they can easily see rodents and small birds, their primary food.
7. Nocturnal primates. Several species of primates can usually be seen after sunset. Most often, these are relatively small animals that initially could not compete with their larger counterparts and switched to a nocturnal lifestyle. These primates have a vision that closely resembles that of humans. The only difference is the presence of large-diameter eyes. With their help, animals capture maximum light, which they see 2-3 times better than humans. Nocturnal primates use this ability to obtain food. They eat various insects and collect fruits growing nearby.
8. Snakes. These reptiles do not always see at night. Those species that have this ability use a different method of obtaining information. It lies in the ability to see an infrared image. With its help, they can detect potential prey in the dark and navigate in space. The most famous snakes with this ability are vipers and various types of boas and pythons.
9. Aquatic inhabitants. Not only terrestrial but also marine inhabitants are endowed with night vision. These include cuttlefish and some types of fish. These representatives of the fauna use their unique abilities to navigate in space, search for food, and arrange shelters from large predators.

How did animals influence the process of creating NVDs?

If you think that we got NVDs solely thanks to the ability of living beings to see in the dark, then you are mistaken. Various representatives of the fauna gave only an idea that people managed to translate into reality. In creating multiple NVDs, dozens of famous scientists who studied light and conducted experiments played a considerable role.

There are several versions about which animals gave people the idea of ​​designing NVDs. One of them prefers cats. These creatures have lived next to people for a long time, so this option is the most plausible. In addition, cats have a unique eye structure and the principle of their functioning in the dark. Back in 1934, the English inventor Percy Shaw was returning to his native Halifax in his car. He drove at night and on a tough road. At one point, a vehicle's headlights hit a cat sitting on the fence. The rays were reflected in the animal's eyes, and Shaw saw their bright glow. At that moment, he came up with the idea of ​​creating a road reflector that could work the same way as the eyes of the cat he saw. Within a few weeks, he received a patent for his invention, which was at the forefront of creating full-fledged night vision.

In addition to cats, snakes pushed people to invent night vision. These reptiles can recognize infrared radiation, which they see perfectly in the dark. At the same time, they are remarkably oriented during daylight hours. This combination interested some scientists, and they studied the vision of snakes in more detail. The results obtained formed the basis for their inventions. They were primitive and intended for specific purposes.

Nevertheless, these inventions helped create full-fledged thermal imaging devices. According to another version, the idea of ​​creating NVDs was given to people by owls. These amazing birds have huge eyes that can collect light even when little of it exists. The first NVDs were equipped with giant lenses, thanks mainly to owls. This enabled the devices to collect maximum light and create an image of satisfactory quality.

What do animal night vision and NVDs have in common?

Using modern night optics, few people think about its connection with the animal world. However, it is pretty significant. The night vision of some animals functions the same way as NVDs, and the eyes of many faunas resemble individual design elements of man-made devices.

Typical signs in animals and NVDs:

1. Appearance of the eyes and lens. The eyes of many nocturnal animals closely resemble the lens lenses of modern NVDs. The organs of vision always have a convex shape and, in most cases, have a large diameter. Something similar is observed in manufactured devices. Their objective lens is always convex. In addition, it is the largest compared to other identical parts (for example, with lenses inside the body or an eyepiece lens). This external resemblance is not an accident. Therefore, when holding any NVDs, remember the nocturnal animals that allow you to see in the dark.
2. Ability to capture minimal light. Most modern devices have increased sensitivity, thanks to capturing even feeble light. A similar effect is observed in 90% of animals who prefer a nocturnal lifestyle. Their eyes are positioned so that most of the outer surface becomes open to streams of light rays. This allows animals to navigate usually in space, even on a cloudy night, and cope with everyday activities without problems.
3. The ability to “see” warmth. Some snakes and lizards can detect thermal radiation emanating from surrounding objects. To do this, particular organs in their body collect such information, process it, and transmit a thermal image to the brain. This feature allows animals to easily find warm-blooded prey even in the darkest corners of our planet (in caves). Modern TI devices also can capture heat. They can also capture heat and transform it into a thermal image.
4. Adaptation to changing lighting conditions. The eyes of some nocturnal animals are designed in such a way that they can quickly adapt to any changes in lighting. This makes it possible to see a clear picture, regardless of the current external conditions. Modern NVDs have a similar ability. By manual or automatic adjustment, they can be adapted to current lighting conditions, thereby maximizing the quality of the image displayed on the screen.

The ability of animals to see in the dark is a fantastic ability that humans are unlikely ever to be able to develop. However, it was she who became the catalyst for the process of creating night vision devices. Today, these devices are used everywhere, bringing significant benefits to people. In the future, NVDs will be improved, and scientific discoveries made by zoologists worldwide will play an essential role in their evolution. This will bring us even closer to many representatives of the fauna and provide an opportunity to understand their lives better.