por Nocturnal animals are those animals that are most active at night: they move, hunt, eat and even mate perfectly in total darkness. That is, they are animals capable of performing all their normal functions at night.
Among the nocturnal animals we can find a great diversity of species and different forms: many are invertebrate animals, many others are vertebrates; some are microscopic animals while others are huge.
This great diversity is a mirror, in turn, of a great variety of physical and behavioral characteristics, since even among individuals of closely related species, very different behaviors and characteristics can be seen to face the challenges of nocturnal life.
Many predators take advantage of the night hours to catch their prey more easily, since nighttime is usually the longest rest time for animals with daytime habit, and it is when they are most unprepared, to put it in some way.
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Characteristics of nocturnal animals
night adaptation
Nocturnal animals come out of their burrows to dominate ecosystems in the stillness and darkness of night, using special instincts to track their prey, mate, move, etc.
However, the physiological functioning of the body of the vast majority of animals is adapted to reach their optimum levels of activity during the day, which has a lot to do with the weather, temperature and light imposed by sunrise and sunset. sun during twilight.
At sunset, guided by instinct, many species seek refuge, since this allows them to protect themselves from predators while they prepare to rest and remain in a state of stillness, recovering their strength.
Capture of stimuli at night
All the adaptations or morphological characteristics that a nocturnal animal must possess in order to fully live at night must provide them with the ability to capture the slightest stimuli, be they movements, rays of light, sounds, smells, among others.
It must be remembered that the night environment is very still, silent, cold and dark, so the forms of all nocturnal animals must focus on being able to detect even the most imperceptible changes in the environment that surrounds them during the night hours. .
The different shapes and strange characteristics that we often see in nocturnal animals are the product of their adaptation to these environments. The long ears of bats, the large eyes of owls, the large snouts of wolves, etc., are just some of these.
The vision
Nocturnal animals have a less developed sense of sight than other senses such as smell, hearing, touch or taste. This is because most of the eyes and specialized vision organs require light to activate.
In the night hours the light is very scarce and for this reason the eyes, which need light to stimulate themselves, are almost useless. However, there are animals whose eyes are adapted to detect even the smallest ray of light.
Vision-related adaptations include larger eyes with more expandable pupils, as well as the presence of a reflective layer behind the retina (the tapetum) that reflects any light ray entering the eye.
When we point a flashlight or reflector at the face of a nocturnal animal, we can see how its eyes reflect the light, as if it were two large crystalline marbles.
Other animals, on the other hand, have infrared vision, that is, they can «see» the temperature of other homeothermic animals that are alive and, therefore, are «hot» (examples of this are some rattlesnakes).
The ear
Insects, cats, birds and mammals are the animals that perhaps have this sense best developed. In many of the species with nocturnal habits, it is easy to see with a simple glance that they have huge ears.
These animals have highly developed eardrums and multiple specialized structures for detecting vibrations that produce sounds in the environment, including capturing and analyzing sounds that occur at great distances.
In the case of insects, on quiet nights or when it stops raining, we listen to the sound that crickets make to attract their mates, who can detect it from kilometers away with highly developed eardrums on their hind legs.
The sense of smell
Many nocturnal animals, apart from using smell to locate their prey, use it to locate their partners, since often females have specific glands in their body to expel liquids with pheromones that «send» specific messages to males.
These messages inform males when they are in heat, gestating, or breeding.
Invertebrates such as moths, ants, spiders and others have smell as their dominant sense, since they are capable of detecting volatile compounds through highly specialized cells for this purpose (olfactory receptor neurons).
The olfactory receptor neuron is usually found on the antennae of insects. However, in arachnids these are distributed around the entire body, with a much higher concentration in the pedipalps.
In nocturnal vertebrates, Jacobson’s organs, located in the upper part of the mouth, serve to detect chemical signals that are carried by the wind (they are chemoreceptors). Humans have it too, just less developed.
Taste
In invertebrates, the specialization of this organ is difficult to demonstrate, since in many places where its receptors are found, other important chemoreceptors for smell are also found.
In the group of vertebrates, as with invertebrates, taste is a chemical sense that requires the particles to be dissolved in order to capture them. These receptors need to be moist and clean in order to identify the chemical particles.
In general, these sensors are found on the head of the animals and are accompanied by serous glands so that the secretions can clean the pores and moisten the environment surrounding the receptors.
The vast majority of mammals, including nocturnal mammals, can detect five tastes: sweet, bitter, sour, salty, and umami. What varies between mammalian species is the location of the receptors for each taste on the tongue.
The touch
This sense is very important in nocturnal animals, especially for animals that live in burrows, such as mice, tarantulas, cockroaches, scorpions, among others. All of these have hairs that are very sensitive to the touch and these can be on their snouts or around their bodies.
The hairs allow them to easily locate and analyze their burrow, without the need to see the walls; they can measure the dimensions of the hole, detect movements when a prey approaches, etc., all this in complete darkness.
Examples of nocturnal animals
Rats (Rattus sp)
They are rodent mammals of the Muridae family that are found almost anywhere in the world, frequently found in city sewers or feeding on garbage, which is why they are closely related to human settlements.
They have a great sense of smell, touch and hearing. In addition, they have perfectly adapted vision for the dark. They are fast animals, with significant climbing skills and impressive teeth that often give them an aggressive appearance.
Elephants (Elephantidae)
Although they may not look like it, elephants are most active during the night hours when they are not in captivity.
These imposing mammals have a great sense of hearing, sight and smell, since very sensitive receptors for smell and touch are concentrated in their trunks.
With their trunk they distinguish between the leaves and the bark of the trees from which they feed, so they use touch, smell and taste at the same time.
Bats (Order: Chiroptera)
Bats are the only flying mammals that exist and are present in almost all parts of the world, except for the poles (North and South).
They have a great sense of hearing and smell, senses that they use to locate themselves in their environment while they fly: by means of hearing they can easily echolocate, since they have the ability to emit low-frequency sounds and detect when they bounce off a surface, which tells them the shape and dimensions of objects.
They are one of the main pollinators on the planet and are also very important in terms of reforestation, since when feeding on a fruit they disperse their seeds with their droppings.
Owls and barn owls (Strigidae sp. and Tytonidae sp.)
Species belonging to these genera are nocturnal hunting birds that feed on small mammals, amphibians, reptiles, small birds, and fish.
They have a highly developed sense of sight and hearing. They generally perch in high places to detect their prey; once they need them, they pounce on them with quick movements and use their powerful claws to subdue them.
Cockroaches (Order: Blattodea sp)
Another type of nocturnal animal related to humans, in addition to rats, corresponds to cockroaches, and that is that these insects can be found virtually anywhere where there are human settlements.
These insects are characterized by their more or less flattened bodies, which can measure between 4 and 8 cm in diameter. They eat almost any food that contains a few carbohydrates.
They communicate through chemical trails, so it is understood that they have an incredible olfactory system.
Also, cockroaches have hairs on their legs that are very sensitive to movements in their environment.
The aye-ayes (Daubentonia madagascariensis)
Often cited as an example of nocturnal animals, the aye-ayes are mammals belonging to the group of apes.
These animals, which only inhabit Madagascar, have enormous eyes, large ears and a very long middle finger that characterize them. They are relatively small (up to 50 cm tall) and usually feed on worm larvae or fruit.
Fireflies (Lampyris noctiluca)
Within the vast number of invertebrates and nocturnal insects, we cannot fail to mention fireflies: some flying beetles that glow in the dark to attract potential mates.
This species of insects, very common throughout Europe and Asia, presents a very evident sexual dimorphism (males and females are very different from each other), since the males have wings and the females do not and these tend to be twice as large than the males.
The serval cat (Leptailurus serval)
This carnivorous feline, which represents the only species of the genus…