The nocturnal animals they 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 nearby species, very different behaviors and characteristics can be appreciated to face the challenges of nightlife..
Many predators take advantage of the nocturnal hours to catch their prey more easily, since usually the night corresponds to the longest resting moment of the daytime animals, and it is when they are most unprepared, so to speak..
Nocturnal animals emerge from their burrows to dominate ecosystems in the stillness and darkness of the night, using special instincts to track their prey, mating, moving, etc..
However, the physiological functioning of the body of the vast majority of animals is adapted to reach their optimal levels of activity during the day, which has a lot to do with the climate, temperature and light imposed by the rising and setting of the 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..
All the adaptations or morphological characteristics that a nocturnal animal must possess in order to live fully at night must provide them with the ability to capture the slightest stimuli, whether they are movements, light rays, 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 appreciate 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 a few of these..
Nocturnal animals have a less developed sense of sight than other senses such as smell, hearing, touch or taste. This is because most eyes and organs specialized in vision require light to activate..
At night the light is very scarce and therefore 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.
Among the adaptations related to vision we can mention larger eyes with pupils with greater expansion capacity, as well as the presence of a reflective layer behind the retina (the tapetum) that reflects any ray of light that enters the eye.
When we aim at the face of a nocturnal animal with a flashlight or reflector 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).
Insects, cats, birds and mammals are the animals that perhaps have better developed this sense. In many of the species with nocturnal habits it is easy to detail with a simple glance that they have enormous ears.
These animals have highly developed eardrums and multiple specialized structures for detecting the vibrations produced by the sounds of the environment, including capturing and analyzing sounds that are produced at great distances..
In the case of insects, on quiet nights or when it stops raining, we hear the sound that crickets make to attract their mates, who can detect it from miles away with highly developed eardrums that they have on their hind legs..
Many nocturnal animals, apart from using smell to locate their prey, use it to locate their mates, since many times 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, in gestation or in the breeding period..
Invertebrates such as moths, ants, spiders and others have the dominant sense of smell, since they are capable of detecting volatile compounds through highly specialized cells for this purpose (olfactory receptor neurons)..
Generally, the olfactory receptor neuron is found on the antennae of insects. However, in arachnids these are distributed around the entire body, with a much higher concentration in 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, only less developed.
In invertebrates, the specialization of this organ is difficult to demonstrate, since in many places where its receptors are found, other chemoreceptors important 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 be able to capture them. These receptors need to be moist and clean in order to identify chemical particles..
In general, these sensors are found on the head of animals and are accompanied by serous glands so that secretions can clean the pores and moisten the environment around the receptors..
The vast majority of mammals, including nocturnal ones, can detect five flavors, sweet, bitter, sour, salty, and umami. What varies between mammalian species is the location of the receptors for each flavor on the tongue..
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 snout or around their body.
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 the movements when some prey approaches, etc., all this in the most absolute darkness.
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, so 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 important climbing skills and imposing teeth that often give them an aggressive appearance..
Although they may not seem like it, elephants are at their peak during the night hours when they are not in captivity..
These imposing mammals have a great sense of hearing, sight and smell, as receptors that are very sensitive to smell and touch are concentrated in the trunk..
With their trunks they distinguish between the leaves and the bark of the trees on which they feed, so they use touch, smell and taste at the same time..
Bats are the only flying mammals that exist and are present in almost all parts of the world, except at 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 flying: through the ear they can easily echolocate, as they have the ability to emit low frequency sounds and detect when they bounce off a surface, which indicates the shape and dimensions of objects.
They are one of the main pollinators on the planet and also have great importance in terms of reforestation, since when they feed on a fruit they disperse its seeds with their excrement.
The 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 rapid movements and use their powerful claws to subdue them.
Another type of nocturnal animal related to human beings, in addition to rats, corresponds to cockroaches, and is that these insects can be found virtually anywhere 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 other food that contains a few carbohydrates.
They communicate through chemical traces, so it is understood that they have an incredible olfactory system.
In addition, cockroaches have hairs on their legs that are very sensitive to the movements of their environment..
Much cited as an example of nocturnal animals, the aye-ayes are mammalian animals belonging to the group of apes.
These animals, which only live in Madagascar, have huge 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 fruits.
Among the vast number of nocturnal invertebrates and insects, we cannot fail to mention fireflies: 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 (females and males are very different from each other), since males have wings and females do not and they tend to be twice as large. than males.
This carnivorous feline, which represents the only species of the genus Leptailurus, It is a not very large nocturnal animal (it can weigh up to 20 kg) that has a small head but huge ears and characteristic very long legs..
This "cat" feeds on other smaller animals, mainly birds and rodents that it hunts at night..
North American river otters are semi-aquatic mammals (they do just as well on land as they do in water), carnivores that belong to the Mustelidae family..
Although they are considered diurnal animals, this species of otter is strictly nocturnal during the spring, summer and fall.
Raccoons are carnivorous mammals typical of the American continent belonging to the Procyonidae family. They are known for their small size and their particular coat, as well as for their nocturnal habits as garbage scavengers in some cities or settlements..