How rats see in the dark and in the light, behavioral features

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06/21/2019 The popularity of rats as pets continues to increase, but they still have not moved away from their role as pests. These rodents are famous for their cunning and intelligence. They bypass the traps people have prepared for them. As many believe, not only intelligence, but also good eyesight helps rodents overcome traps. Is this really true? The article describes how rats see.

Pet age in human years

In terms of the human life cycle, a pet rat will live somewhere between 3-5 years.
Humans are considered elderly starting at about 60 years of age, which would be about two years of age for a rat. Old age is a guarantee of decreased performance and mobility; therefore, it is a good way to determine the general age of a pet rat. One day in the life of a rat is equal to 26.7 days in human years, which is approximately 1 human day equal to a month in the lifespan of a rat. With this in mind, you can expect a rat's physical performance to decline after about 2 years, which is essentially a sign of old age.

Do rodents see colors?

The human eye contains two types of light receptors:

• rods (perceive dim light, provide the ability to see in the dark);
• cones (catch bright light, distinguish a range of colors).

The rat eye contains the same receptors, but unlike human ones, they are located less closely to each other. This feature is reflected in color perception. The retina of the animal’s eyes perceives the following types of spectra:

• medium wave;
• shortwave;
• ultraviolet.

Rats can only distinguish between green and blue colors, and do not recognize shades.

The density of receptors is not the only difference between the retina of humans and rodents. Another difference is the ratio. If humans have cones 5% of the total number of receptors, then rats have only 1%. Thus, 99% of rat receptors are rods.

It is worth noting that the structure of the eyes does not allow rats to distinguish colors. The world for these animals does not play with bright colors. Vision in rats is based on the perception and assessment of the brightness and dimness of light radiation.

How pets see the world (12 photos)

A cat rushes from the other end of the room after a fly, but at point-blank range does not see a piece of sausage placed right in front of it, and at dusk the parrot crashes into you on landing? The visual characteristics of our pets are to blame for everything. Cats

When talking about excellent vision, a person means the ability to see clear, colorful images near, far and in peripheral vision. Many of the parameters familiar to us turn out to be insignificant for a cat. The vertical pupil in the eye of a predator protects it from direct sunlight, so in bright light it narrows to a thin slit.

Near the photoreceptors of a cat’s eye there are special formations - tapetums, which “intercept” light and direct it back to the retina, which allows the cat to see in the twilight as during the day, and at night as a person sees in the twilight. Thanks to tamepum, a cat's eyes glow in the dark.

All cats perceive the world in shades of gray, green and blue. Surprisingly, cats are not distinguished by visual acuity in the usual sense; they see small details blurry, since during the hunt they focus mainly on sounds and movements. In addition, the vision of a night hunter covers 270 degrees, with each eye distinguishing up to 45% of the image, thanks to which the cat is able to calculate the distance of a long jump with an error of up to 3-4 centimeters.

For a long time there was an opinion that dogs see the world in black and white. In fact, they distinguish colors, but in a slightly different way. The human retina contains 3 types of cones responsible for color perception: the first are sensitive to long-wave radiation (red and orange), the second to medium-wave radiation (yellow and green), and the third to short-wave radiation (blue and violet).

Dogs lack the first type of cone, and as a result they are not sensitive to orange-red color and can perceive it similarly to yellow-green. In this case, the color that the owner identifies as blue-green will be white for the dog, but the dog distinguishes shades of gray more than other creatures. The field of vision of dogs is “stretched”, as a result of which a picture of 270 degrees falls into it (for comparison, the same parameter for human perception is 60-70 degrees less).

Dogs, like cats, are guided by movement, and are able to perceive a stationary object at a distance of 600 meters (while they catch a moving one from 800-900 meters). Interesting fact: for dog breeds with floppy ears, the main thing is vision, while those with erect ears rely primarily on hearing.

These rodents have long been domesticated, but even if a rat is an uninvited guest in your house, you can be sure that it does not even suspect your presence at the other end of the room if you do not move and do not call for help with a piercing cry.

The fact is that the maximum distance for a rat’s vision is only about 1 meter, this is due to panoramic vision and laterally placed eyes, which help the rat to distinguish surrounding objects. Rat binocular vision, unlike humans, captures several separate images from different angles.

Rats can perfectly distinguish the distance to an object, but due to the low coverage, this is only relevant in a limited area. Rats also lack color vision. Like dogs, they distinguish between gray colors well and perceive the blue and green parts of the spectrum, but for them the red color is equivalent to absolute darkness. But rats see ultraviolet radiation perfectly, and even distinguish shades of ultraviolet.

Pet birds have very good eyesight. The viewing angle, thanks to the position of the eyes, is 360 degrees, so that not a single detail in the environment can be hidden from Kesha. Of course, parrots see the world in color, as evidenced by the bright plumage created for individuals to recognize each other.

Pet birds have very good eyesight. The viewing angle, thanks to the position of the eyes, is 360 degrees, so that not a single detail in the environment can be hidden from Kesha. Of course, parrots see the world in color, as evidenced by the bright plumage created for individuals to recognize each other.

The horse's viewing angle is 350 degrees, which means that the horse does not see only what is under his muzzle, above his forehead and right in front of his nose. That's why a horse won't pick up a piece of apple lying right in front of it - it simply doesn't see it. But horses see perfectly in the dark and are able to accurately estimate the distance to objects.

The main feature of their vision is monocularity, which often causes the fearfulness of horses: they see two different pictures with two eyes, and not a single image, as is the case with human vision, and the horse is often frightened by an object that has suddenly moved from one field of vision to another.

Due to the presence of a “blind spot”, the horse does not see an object located in the area in the middle. In addition, a horse's vision range does not exceed 500 meters, and it slowly adapts to color changes, which is why horses are often frightened by the glare of the sun and unexpected shadows on the ground. The color spectrum of equine vision is quite diverse, although horses have a weakness for blue and green shades.

Reptiles
Few people dare to have such a charming pet in their home, but if you are the happy owner of a snake, you should know how it sees its owner. The snake's eye is covered with a thin, leathery film, the result of fused eyelids. Towards the beginning of molting, the snake's eyes become cloudy, and this makes vision difficult. In the future, the film will come off when you change the “clothing”.

It turns out that snake vision deteriorates several times during its life and returns to the reptile. Diurnal snakes have a round pupil, while nocturnal snakes have a narrow vertical pupil. Binocular vision allows the snake to form an image from the retinas of both eyes, but this vision is focused primarily on thermal information. Thus, a snake is more likely to see the contours, size, distance to another animal, and this image allows one to identify a warm-blooded mouse on cool soil or a cold-blooded frog among the warm vapors of the earth. The picture shows an example of how a snake sees a person.

Source

Fact 1: Rat vision – external and internal

In order to imagine how rats see, it is enough to recall human colorblind people with extreme manifestations of the disease. Animals practically do not distinguish colors; the whole world for them is a collection of spots of different sizes and intensities that are in motion. Rodents' external vision is very poor, but they don't need it. Rats hear perfectly, distinguishing the direction and distance of even a subtle rustle, and can determine its cause. In addition, the animals have a delicate sense of smell and touch.

There is another incredible fact. Scientific experiments with rats have shown that test subjects have inner vision. In humans, this is called premonition, or the ability to see possible developments of events. This theory is supported by a well-known fact: rodents, which live in large numbers on board a ship, leave before it sinks. There are also more specific confirmations. For example, in the Stalingrad hell, animals left the city en masse before the next air raid. They also feel nuclear tests, running away from test sites several hours before the events.

Characterized by intelligence

Yet the secret to the success of this species lies largely in its intelligence. It’s not for nothing that the Polish zoologist Miroslav Gushch called him an intellectual of the animal world.

Here's the plot: a rat trap with poisoned bait. Do you think this is the end of the rodent? No matter how it is. Rats are suspicious of new foods. And if their poor comrades fall for the poison, the rest will quickly realize what’s going on and won’t touch the bait.

Some scientists are even sure: rats deliberately send their friends, who are on the lower steps of the hierarchy, to taste the bait. And if they went to their forefathers, the old experienced animals will stain the poisonous food with droppings.

Moreover, observers note that they are even able to shake the dangerous bait out of the rat trap and bury it in the ground - so that careless youth are not in danger.

Rat.

visualhunt.com

Attitude towards a person

The decorative albino rat is a tame and loving animal. He is trainable, cunning and intelligent. Many owners claim that the rat quickly learns to open the lock on the cage. She thinks quickly, and is significantly different from her dark brothers. Watching your pet play is a pleasure. The Internet is full of videos where albinos willingly perform various tricks, climb around the room, and simply live.

A kind and gentle rat loves its owner. I’m ready to spend whole days on my hands, knees, or in my pocket. Having settled comfortably on a person, she shows her affection with all her appearance. She climbs into her arms to be stroked on her back.

Regular communication with your pet can be turned into training. The rat quickly remembers its name and the names of its cage neighbors. It is better to train animals to communicate with other pets gradually and carefully.

Night rumble

Don't expect your rat to follow the same schedule and rhythm of life as you. On the contrary, be prepared for the fact that the rat is active at night and sleeps during the day. The period after dinner is a great time to socialize and play with your pet. The attempt can be resumed early in the morning - whatever is more convenient for you. You may also enjoy the funny positions in which rats like to sleep - lounging on their backs, curled up into a tight ball, etc.

Scavenger Hunters

Rats have a habit of picking up and dragging to a secluded place something that might be suitable for playing or chewing. Rats steal and drag objects made of wood, plastic and rubber into their lair. They are happy to carry objects made of paper or fabric. Rats are also great masters at arranging all kinds of stashes and food supplies.

Fighting boxers

Not only kangaroos have shown themselves to be boxing fans! Rats also love to box - they stand on their hind legs and heartily begin to kick each other with their front legs. But this is not for fun: two rats find out which of them is the alpha male, the dominant male. Rats have a very developed social hierarchy. Sometimes you can see how, instead of a desperate fight, rats stand up frozen nose to nose. They may not get up - rodents have many different variations on this theme.

Rat bites

If a rat bites or licks you, perhaps this is his way of showing his love.

Rats also have a wonderful sense of smell, and may well bite you if you carelessly took something edible before entering the cage. Before working with a rat (and also after), wash your hands thoroughly with soap and water.

Teeth grinding

This phenomenon usually accompanies the bulging of the eyes described above. There is no need to be scared, the rat belongs to the rodent family, and its teeth are constantly growing. When a rat grinds its teeth, it tries, so to speak, to moderate their growth, to make sure that they do not grow too quickly. Moreover, teeth grinding in rats is similar to purring in cats - this is what they do in moments of relaxation and peace. This creates vibrations that help the eyeball protrude - therefore these two phenomena are interconnected

At the same time, a rat may grind its teeth when it is scared or in pain, so pay attention to the circumstances under which this happens (for example, when you pet it or vacuum near the cage).

A rat's sense of smell is a billion times greater than the human sense of smell.

Interestingly, the rat's tail, which everyone considers ugly and disgusting, is the most valuable both in itself and in scientific research. Most often, drugs are injected into the tail vein. The tail retains all the body heat: the rat hugs the tail and warms itself - this is its heating pad.

The rat also has superpowers. While the human ear can hear sounds with a frequency of 30 decibels, a rat can perceive sounds with a frequency of 0 decibels: this means that it can hear our breathing. A rat's sense of smell is a billion times better than ours. On the other hand, rats have poor eyesight, especially lab rats.

Is the rat a threat in scientific research?

A rat can carry 14 parasitic and 26 infectious diseases. However, they do not affect the rat itself, but only the vector. However, all animals we buy go through a period of inspection and quarantine, during which the rat receives all the necessary drugs against hidden pathogenic microorganisms and becomes relatively harmless to us.

Of course, working in a vivarium is a dangerous occupation, but from occupational diseases it can only be a cumulative allergy to wool. You just have to take precautions and everything will be fine.

Are a lab rat and a pet shop rat different animals?

— A laboratory rat and a decorative rat are the same type of animal. But decorative rats may have spots. They are bred and fed differently. A rat in a cage should be busy, it should constantly play. Our rats are quiet, they sleep constantly.

Can a rat attack a person?

- If he is hungry or feels threatened, he can easily nip at the ears of a sleeping person. The rat secretes an anesthetic in its saliva so that the sleeping person does not feel anything.

Why are there so many rats in the city?

— Probably because we have a lot of food for them: cafes, restaurants, the private sector, where many people raise cattle. But this is already a question for the Sanitary Inspectorate. They must fight rats and carry out forced deratization. Unfortunately, our people have to fight rodents on their own, and they do not always do it competently and do not always use the right drugs. The Chinese smuggled insecticide “Executioner” has already killed 26 people in the city.

Features of albino rats

Albino rats have a number of features that distinguish them from ordinary gray rodents. Such rats live no more than 1.5 years. Due to health problems and unfavorable environmental conditions, they have weak immunity. This distinguishes them from their dark-haired relatives. For comparison, representatives of their genus with dark fur live up to 3 years.

They are practically unable to adapt and survive in the wild, so it is not worth releasing them into the wild - this will lead to the inevitable death of the animals.

Sometimes you can find a semi-albino rat with dark eyes and white fur with a grayish tint. Such animals have stronger immunity than their white relatives. Semi-albinos get sick less often and adapt to their environment much better. As a result of crossing them with albinos or gray pasyuks, in almost 100% of cases, the offspring appear with dark hair.

The albino rat in the photo is too noticeable on the grass: the lack of camouflage does not give rats a chance to survive in nature

Albinos are quite fertile, tolerate captivity well, and are light in weight. And these are the main qualities for which they are so valued in laboratories. As a result of research, scientists have revealed a fairly high level of intelligence in white rats. In addition, rodents have the ability to empathize and sympathize with their relatives. There are known cases when albinos showed altruism.

Attitude towards a person

White rodents are quite trainable; they are quite cunning and intelligent, although they cannot be compared with their wild relatives struggling for survival. Albinos easily remember their nickname, as well as the names of other pets living in the same territory with them.

It is worthwhile to properly lock the lock on the cage door, as these animals can learn to open simple latches.

A simple latch on the door is not an obstacle for an albino rat

They have a good-natured and gentle disposition towards humans, unlike their wild ancestor. These rats are very sociable and love to hang around people, begging for affection and treats. They are easy to hold and allow you to stroke your back.

Important! With regular communication with your pet, you can quickly tame it. But we must remember that these rodents have excellent memory and remember well those who hurt them

EYE DISEASES IN DOMESTIC MICE AND RATS

Due to the small size and difficulty of mounting mice and rats, ophthalmic examination of mice and rats requires some skill. The belly and tail are best grasped in the palm of your hand, and the head of the animal is fixed with the thumb and forefinger.

A large, open-ended syringe can make it easier to restrain small rodents. The head comes out of one end of the syringe, and the tail comes out of the other. It is easy to secure the head with your thumb. Taking frequent breaks helps minimize stress. General anesthesia is necessary in very rare cases.

In mice and rats, the lacrimal system consists of three structures: the intraorbital gland, the extraorbital gland, and the Gardner's gland.

The intraorbital gland is located near the attachment of the masseter muscle and is often mistaken for a neoplasm due to its unusual location.

In Gardner, the gland is located behind the eyeball, light pink in color and U-shaped. It has a single exit channel that opens at the base of the third eyelid. Microscopically, this gland appears foamy due to its higher lipid content compared to other lacrimal glands.

This gland is the only gland in mammals that has the merocrine type of lipid secretion. It is believed that the Gardner's gland contains pheromones, which play an important role in the care of the scalp in underground animals.

In rodents, this gland contains porphyrin, a reddish-brown pigment, and additionally secretes melatonin, which should act as an electrodermal photoreceptor. Ruptured or excessive production of oral tears is often caused by eye irritation or nasolacrimal duct obstruction and inflammation of the salivary and lacrimal glands.

Too much production of these red tears is called chromodacryorrhea and can be mistaken for blood. Ultraviolet light makes the difference: porphyrin should glow under ultraviolet light, while blood does not.

Eye irritation can be caused by underlying conditions such as keratitis, conjunctivitis, or irritation from contaminated litter or high levels of ammonia in the environment. Obstruction of the nasolacrimal duct caused by improper blockage or overgrowth of the lower posterior teeth. The tumor is responsible for the obstruction. Dental treatment improves eye condition.

The most common disease of the lacrimal system is dacryodenitis or inflammation of the Gardner's glands. The most common clinical sign in this condition is chromodactyly. Dacryodenitis is very often associated with diaodacryodenitis virus (SDAV), which is a coronavirus and is genetically similar to hepatitis virus in mice, as well as Parker's coronavirus in rats. This virus is a common problem in rats, especially when they live in a colony with breeders. The virus is highly contagious and spreads very quickly.

Gardner's gland tumors are quite common in mice and rare in rats. In most cases, these tumors are benign, and the most common symptom is bulging eyes.

Care

Caring for an unpretentious animal is not difficult, you just need to follow the rules of hygiene and feeding. However, these things should be taken seriously. Rodents, especially decorative ones, are susceptible to various kinds of diseases. Their diet should be balanced and the food fresh.

What to feed

Due to its physical characteristics, the rat is an omnivore: it happily eats meat and vegetable dishes, cereals and porridges.

To maintain the balance of minerals and vitamins in feeding, you need both boiled porridge and raw cereals:

• buckwheat;
• corn;
• rice;
• wheat;
• barley.

Sprouted grains, seeds, and nuts are welcome. Good digestion will be ensured by the consumption of fermented milk products, especially since rodents love them. The animals love and eat meat and fish, offal and boiled eggs. Vegetables and fruits are necessary as a source of vitamins and organic acids, but in moderation.

You cannot feed the following foods:

• chocolate;
• raw vegetables - cabbage, potatoes, spinach;
• sweets;
• spicy, salty, smoked, fried;
• alcohol;
• soda.

Important! There is no need to worry about the amount of food - rodents have a developed sense of fullness, and they never eat more than they need.

Hygiene and bathing

Proper care that will ensure a long and healthy life for your pet includes a clean home.

The cage requires daily cleaning:

• washing dishes;
• changing water (it should always be fresh);
• replacing the filler and cleaning the tray.

The cage should be washed with any disinfectant twice a week. Hygienic procedures are also necessary for the animal. It is not necessary to wash it yourself - just provide a container with soapy water, and the pet will wash itself. Rats naturally love water: they swim, dive and even hunt well there.

Rat breeders have many different opinions about trimming claws, pros and cons. If we think logically: in nature, an animal grinds its claws down almost every day - on stones and trees. But sitting at home in a cage or running around on the sofa, it is impossible to do this. To prevent claws from growing into the pads, causing pain to your pet, it is advisable to purchase miniature nippers or scissors. It is recommended to check with your veterinarian how often and how to carry out the procedure correctly.

Video: bathing rats

Possible diseases and their prevention

Domestic rodents do not come into contact with street animals that can carry infections and bacteria. Typically, tame animals have a well-developed immune system, so health problems can only be hereditary, or acquired as a result of errors in care.

Important! Each genotype has its own predisposition - for example, megacolon (an abnormality of the large intestine) is hereditary in Blazes.

Factors provoking diseases:

• improper diet;
• poor quality products;
• lack of hygiene (personal and indoor);
• drafts, cold or heat, high humidity.

These errors in caring for your pet can cause the following diseases:

• Teaser's disease (an acute infection characteristic of rodents);
• pseudotuberculosis;
• pneumonia;
• pituitary tumor;
• tail necrosis;
• pneumococcosis.

Rarely, mycoplasma infections occur as a result of the spread of the pathogen in the sales environment or in the breeder.
Therefore, a newly acquired animal needs to be quarantined for some time. Within 7–10 days, you need to observe your behavior and health status. Also read about why your pet rat itches.

Among the preventive measures:

• purchasing an animal from trusted breeders;
• a well-designed diet that excludes prohibited foods;
• kept in a dry, moderately warm place, without drafts;
• exclusion of stressful situations.

At the first examination, you can get competent advice from a rodentologist on the conditions of keeping the rodent. Vaccination will help eliminate health problems. The specialist will select a vaccine against diseases needed according to the animal’s belonging to a particular species.

How to train and play with your pet

It is not difficult to train a rat: from the first days of communication, it recognizes its owner and willingly makes contact. Playing with a candy wrapper on a string or climbing a rope - in general, everything that requires movement gives her pleasure. During such fun, the rodent learns to trust the owner and remembers repeated gestures or sounds.

Video: how to train a rat

A smart baby quickly remembers his name and responds to it. The animal easily masters commands: bring an object, jump over an obstacle and many other tricks. The main thing is to focus on a certain action, for example, then give out a treat.

Did you know? During research, scientists from the Chinese University of Hong Kong discovered a gene in rats that protects the body from sexually transmitted diseases.

Can drive a car

The extraordinary nature of these animals is also evidenced by an experiment recently conducted by scientists from the University of Richmond - the team of Professor Kelly Lambert, who built small cars.

The chassis and drivetrain were made from a robot car kit, and a clear plastic food container became the body. Explaining the idea of ​​a steering wheel and pedals to the rats was too difficult. Therefore, management has been simplified. The rat had to stand on the plate and grab the copper rod - due to this, the circuit was closed and the engines turned on.

It's a paradox - but rats learned to drive a car. Three five-minute sessions per week for eight weeks were sufficient. Naturally, treats were also used. It is characteristic that those who had previously lived in a complex environment - multi-level cages with different objects for games - were more trainable.

A rat is taught to drive a car.

arstechnica.com

How they see in the dark

The idea that cats navigate in pitch darkness is a myth. The animal sees in minimal light. A cat only needs 10% of the lighting that a human needs. People cannot see anything in such illumination. But this animal is a predator, so its eyes are equipped with additional receptors that have increased sensitivity to light. The tapetum on the back wall of the retina, like a mirror, reflects light twice, which is why cats' eyes glow so much in the dark. In fact, the eyes do not glow, but reflect the rays that hit them.

Cats look at us with multi-colored eyes. Colors like yellow amber, blue sea, blue sky, green grass or bright gold

Good orientation in the space of a dark room is explained by the fact that vision is not the only organ with which cats perceive the world. The secret of the animal is in the especially sensitive organs of touch - vibrissae.

How do animals perceive color?

Features of cat vision

The cat's organ of vision differs sharply from the human one in structure and ability to perceive space. They have large, round eyes with a convex lens. The viewing angle of space is 270 degrees.

A special feature of cats is stereoscopic vision. Each eye receives its own image of an object, which is then combined by the brain into one three-dimensional picture. As a result, the predator receives accurate information about the location of the prey and the distance to it.

Everything that the left eye sees goes to the right side of the brain and, conversely, the right eye transmits the picture to the left half

The genetic memory of a predator makes animals react to moving objects. Stationary animals are practically of no interest to them. Watching a moving object, the animal begins to actively move its head up and down: this is how the cat changes its viewing angle and focuses on the prey. This natural ability helps the predator calculate the distance to the prey down to the millimeter, which is why the cat’s jump is so accurate.

The special sensitivity of a cat's eyes is directly related to the structure of the pupil. It is located vertically and has increased elasticity. In bright light, it narrows, limiting rays from reaching the retina. Lack of lighting causes the pupil to dilate greatly, allowing more light to enter.

Color difference

The human eye contains 2 types of light receptors - cones and rods. The first perceive bright light and different colors. The latter capture dim light and allow you to see in the dark.

The rat's eye also contains rods and cones, but their density relative to each other differs. This affects the perception of colors. The retina of a rodent eye detects short- and medium-wave spectra. The rat sees blue, ultraviolet spectrum colors and green.

The retina of a rodent's eyes consists of 99% rods. Cones occupy only 1%. A person has 5% of them. An interesting fact about the rat is that it does not see the colorful tone, does not distinguish colors. Much more important for her is the brightness and dimness of light radiation.

What is vision?

Vision is the process of processing images of objects in the surrounding world.

• carried out by the visual system
• allows you to get an idea of ​​the size, shape and color of objects, their relative position and the distance between them

The visual process includes:

• penetration of light flux through the refractive media of the eye
• focusing light on the retina
• transformation of light energy into nerve impulse
• transmission of nerve impulses from the retina to the brain
• processing information with the formation of a seen image

Visual functions:

• light perception
• perception of moving objects
• field of view
• visual acuity
• color perception

Light perception is the ability of the eye to perceive light and determine varying degrees of its brightness.

The eye contains two types of light-sensitive cells (receptors): highly sensitive rods, responsible for twilight (night) vision, and less sensitive cones, responsible for color vision.

The process of adapting the eye to different lighting conditions is called adaptation. There are two types of adaptation:

• to darkness - when the light level decreases
• and to light - with increasing light levels

Light perception is the basis of all forms of visual sensation and perception, especially in the dark. The light perception of the eye is also influenced by factors such as:

• distribution of rods and cones (in animals, the central region of the retina at 25° consists predominantly of rods, which improves night vision)
• concentration of light-sensitive visual substances in rods (in dogs, the sensitivity to light of rods is 500-510 nm, in humans 400 nm)
• the presence of a tapetum (tapetum lucidum) - a special layer of the choroid of the eye (the tapetum directs back the photons that pass to the retina, causing them to once again act on the receptor cells, increasing the photosensitivity of the eye, which in low light conditions turns out to be very valuable) in cats the eye reflects 130 times more light than a person (Paul E. Miller, DVM, and Christopher J. Murphy DVM, PhD)
• pupil shape - the shape, size and position of the pupil in various animals (the pupil can be round, slit-like, rectangular, vertical, horizontal)
• the shape of the pupil can tell whether an animal is a predator or a prey (in predators the pupil narrows into a vertical stripe, in preys into a horizontal stripe - scientists discovered this pattern by comparing the shapes of the pupils in 214 species of animals)

So, what are the different pupil shapes:

• Slit pupil - (in predatory animals such as domestic cats, crocodiles, gecko lizards, snakes, sharks) allows you to more accurately adjust the eye to the amount of light around, so that you can see in the dark and not go blind in the midday sun

• Round pupil - (in wolves, dogs, big cats - lions, tigers, cheetahs, leopards, jaguars; birds) because they are spared the need to see well in the dark

• The horizontal pupil (herbivores) allows the eye to clearly see what is happening near the ground and covers a fairly wide panorama of the eyes, protected from direct sunlight from above, which could blind the animal

What are the visual fields of animals?

Field of view is the space perceived by the eye with a fixed gaze. There are two main types of vision:

• binocular vision - perception of surrounding objects with both eyes
• monocular vision - perception of surrounding objects with one eye

Binocular vision is not present in all species of animals and depends on the structure and relative position of the eyes on the head. Binocular vision allows you to make fine coordinated movements of the forelimbs, jumping, and move easily.

For predators, binocular perception of hunting objects helps them correctly assess the distance to the intended victim and choose the optimal attack trajectory. In dogs, wolves, coyotes, foxes, jackals, the binocular field angle is 60-75°, in bears it is 80-85°. In cats, 140° (the visual axes of both eyes are almost parallel).

Monocular vision with a large field allows potential victims (marmots, gophers, hares, ungulates, etc.) to notice the danger in time. reaches 360° in rodents, 300-350° in ungulates, and more than 300° in birds. Chameleons and seahorses can look in two directions at once, because... their eyes move independently of each other.

Visual acuity

• the ability of the eye to perceive two points located at a minimum distance from each other as separate
• the minimum distance at which two points will be visible separately depends on the anatomical and physiological properties of the retina

What does visual acuity depend on?

• on the size of the cones, the refraction of the eye, the width of the pupil, the transparency of the cornea, lens and vitreous body (comprising the light refractive apparatus), the condition of the retina and optic nerve, age
• The diameter of the cones determines the value of maximum visual acuity (the smaller the diameter of the cones, the greater the visual acuity)

Visual angle is the universal basis for expressing visual acuity. The normal sensitivity limit of the eye of most people is 1. In humans, to determine visual acuity, the Golovin-Sivtsev table is used, containing letters, numbers or signs of various sizes. In animals, visual acuity is determined using (Ofri., 2012):

• behavioral test
• electroretinography

The visual acuity of dogs is estimated at 20-40% of the visual acuity of humans, i.e. a dog recognizes an object from 6 meters, while a person recognizes an object from 27 meters.

Rat King - truth or myth?

The Rat King is recognized as a rare phenomenon. The tails of several rodents become so tightly tangled that the rats cannot free themselves and untangle them.

Such rats quickly die because they cannot coordinate their actions to obtain food or simply direct movement. Such cases are very rare: throughout the world, over a long period of time, there are only a few dozen such remains. Often these discoveries were made by accident by ordinary people - on their farms, basements or near mills, but despite this, a huge number of myths about such monsters arose, especially in ancient times.

The most interesting thing in these stories is that no one has ever seen such kings live; only rat remains testified to this. To date, there is not a single photo, much less a video, to prove this phenomenon.

Of course, it is difficult to imagine that the tails were intertwined after death, i.e. It is logical that the knot arose during life - the constant bustle of rats could lead to this. A rat can live without food for a maximum of 4 days, i.e. Confused and unable to come to an agreement, such animals are doomed to death.

There is a version about the “fusion” of tails due to cramped circumstances: in a cramped and narrow space, sooner or later the tails will become connected. Or, according to another version, the tails may become tangled due to contamination, food debris, blood or sticky substances sticking the rats' tails together. Another theory is that the tails freeze together when rats try to stay warm in cold weather. In any case, after waking up, the rats try to run away in different directions, only tightening the knot more.

It can be gigantic

An ordinary person understands a rat as the most common species on the planet - the Norwegian, or gray (Pasyuka), and its domesticated relative, which is bred in homes.

There are legends that these creatures grow almost to the size of a cat. This is not true - pasyuki do not grow. The largest of them rarely reach 50 centimeters including the tail and gain 450 grams.

But... In nature, there is not only this type of rat. In New Guinea, during the filming of a BBC nature film in 2009, a completely new species was discovered in the crater of the Bosavi volcano.

It was named the Bosavi woolly rat. This miracle of nature reaches 82 centimeters (including the tail). This “rat” weighs about 1.4 kg. And she is not at all afraid of a person whom she has never seen during her volcanic life.

Rat.

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Rat.

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Rat.

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Features of the skeletal structure of the rat

There are a total of 264 bones in the rat skeleton. The spine has 3 sections: cervical, thoracic and sacral.

The rat’s skull is elongated and consists of 17 bones, 6 of which are unpaired. Like all mammals, the skull is divided into 2 parts: the brain and the face. By the way, as for the brain, its mass is about 1% of the total weight of the individual.

The tail is thick and long, reaching 85% of the length of the animal’s body. Interestingly, females always have a longer tail. The tail is not covered with hair: here we can see scaly rings covered with yellow fat and bristles.

The structure of teeth, or why do rats always chew something?

A rat's incisors do not have roots and continue to grow throughout their lives, while there is enamel only on the front surface of the tooth, and there is no such coating at the back. Thus, the teeth are ground unevenly and are shaped like a carpenter's chisel.

It is the continuous growth of the incisors that makes rats constantly chew on something. Their teeth grow so rapidly that if the animal cannot grind them down, then, soon, it simply will not be able to completely close its mouth, which will cause discomfort. That is why the cage should always contain small wooden blocks, sticks and tree branches - everything that the animal can chew without harm to its health.

Why doesn't a dog have the visual acuity of a human?

Dogs, like all other mammals except monkeys and humans, lack the central fovea of ​​the retina (the area of ​​maximum visual acuity). Most dogs are slightly farsighted (hyperopia: +0.5 D), i.e. they can distinguish small objects or their parts at a distance of no closer than 50-33 cm; all objects located closer appear blurry, in circles of dispersion. Cats are nearsighted, meaning they cannot see distant objects as well. The ability to see well up close is more suitable for hunting prey. The horse has low visual acuity and is relatively myopic. Ferrets are myopic, which is, no doubt, a reaction to their adaptation to a burrowing lifestyle and searching for prey by smell. Ferrets' nearsighted vision is as sharp as ours and maybe even a little sharper.

Thus, the eagle has the sharpest vision, then in descending order: falcon, man, horse, dove, dog, cat, rabbit, cow, elephant, mouse.

Ways to see a pig in the dark

Like other rodents, guinea pigs have good orientation and vision in dark rooms. Despite the virtual absence of helplessness at night and the ability to perform basic operations, vision in rodents is still considered daytime. Because of this, it is ideal to place the cage in a well-lit area, but away from direct sunlight. Experiments have been conducted to prove the negative influence of darkness on the animal. Degradation, disease, and mutations of various types occur. It has been noted that in the process of survival, animals are better oriented in space thanks to hearing and smell rather than vision.

How vision changes with age

Like any other mammal, rats' vision declines with age. This is a natural phenomenon. Rats are not long-lived at all, so already at the age of two they see much worse than young individuals. The older the rodent, the faster the cells in the retina are destroyed. Good nutrition and living conditions will, of course, slow down the loss of vision a little, but this is an irreversible process.

We advise you to find out how to determine the sex of a decorative rat.

It is believed that rats are small, intelligent and incredibly cunning creatures with excellent memory. Despite the fact that their ability to see is not the best and few people can envy this, these rodents easily bypass traps and traps. Over time, they adapted and learned to use the strengths of their so-called “weak” vision.

Visual orientation

The rat's vision has its own characteristics, complemented by the characteristics of the brain and thinking. The animal is well oriented in the space familiar to it, since it remembers the location of objects.

A study was conducted where rodents moved through a maze. After the structure was turned over, the animals strayed from their intended course. When the objects were moved along with the maze, the rodents behaved as usual.

Pests can clearly see objects located at a distance of 50 cm. They distinguish whether the path ahead is clear within 75 cm. To determine the closer location of objects, they use the organs of touch - the mustache.

What kind of vision do rats need to know in order to outwit rodents and get rid of them in a timely manner? It is also worth considering that as animals age, their vision decreases. Rats do not live long, so their vision begins to deteriorate after 2 years of life. This explains the fact that older individuals are more likely to fall into a trap.

How to feed baby rats

During the first 14-16 days, rat cubs feed only on mother's milk. Then they begin to become more active, crawling around the nest and even trying the food that their mother brings. 3 weeks after birth, the pups eat vegetables, grain mixtures, lean meat, eggs, cottage cheese, and fresh herbs.

There are often situations when small rats are left without maternal care. This happens for various reasons:

• Mom doesn't have enough milk;
• the female died after giving birth;
• someone touched the little rat with their hands, and the mother abandoned him.

In each case, the babies will have to be artificially fed, otherwise they will die.

Orphaned cubs must be kept warm. A lot of paper napkins are placed in the nest. They are replaced as they become dirty. To warm little rats, you can use a rubber heating pad or a plastic bottle with warm water.

To feed the litter, a cat or dog milk substitute, which is sold at a veterinary pharmacy, is suitable. If you can't find it, you can use baby formula. To increase the nutritional value, add a little condensed milk with a fat content of about 12% or glucose, as well as a little calcium gluconate.

It is convenient to feed small rats from an insulin syringe without a needle.

The animal is carefully taken vertically in the left hand, and the head is held with the thumb and forefinger. The tip of the syringe is inserted into the mouth

The piston is moved very slowly so that the little rat does not choke.

In the first week of life, rat pups are fed every 1.5 hours, then every 2.5-3 hours. At this age, they eat no more than 0.3 ml of formula at a time. It is quite simple to determine that the baby is full - his stomach is clearly visible through the thin skin on his stomach. It looks like a white transverse stripe. If its length is two-thirds the width of the body, then the stomach is full. Week-old rat pups eat about 0.5 ml of milk at a time, and at the age of 10-12 days - 1 ml.

A real homebody

Over the entire history of living next to humans, rats have made dizzying journeys - they populated almost the entire planet on ships and trains. But biologists still say: they are homebodies.

No, sometimes they get the wanderlust itch. For example, in 1966, hundreds of thousands of rats in Thailand, for no apparent reason, walked around the country en masse and swam across rivers. But, as they say, the exception only confirms the rule.

During Soviet times, a scientist tagged black rats living in the Abkhazian forest. Two months of surveillance showed that the rats did not dare move even fifty meters away from the nest.

The gray rats that were spied on in Volgograd were a little bolder - they could break away from their home by 100-120 meters. But with a sufficient amount of food, they staunchly adhere to their habitable place. In general, home sweet home.

Rat.

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Selectivity in relationships

Professor Mason continued her research on empathy and rats and presented even more surprising results. Her later experiments, conducted in 2014, showed that rats are “selective” about who they empathize with.

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If they are not “familiar”, a free rat will not free a trapped one. The study yielded the same results when the free rat was raised in isolation and not socialized with its mates. Essentially, this means that if a rat has never seen another member of its species, it will not open the door.

The study concluded that empathy was based on the rat's social experiences, but was not limited to individuals it knew. A free rat would help an alien if it ever crossed paths with it.

Suspected of destroying dinosaurs

What can I say, a rat is a bad neighbor for a person. She is not afraid of ruining her figure, and besides, she is not capable of starving (3-4 days without food is a death sentence for her). Therefore, he is always looking for something to snack on. In a year, she can eat up to 10 kg of food. And spoil it even more.

Many years ago, Americans conducted an experiment: in a food warehouse they gave rats complete freedom for two months. It is possible that after summing up the results they had to take large doses of sedatives.

It turned out that the rodents ate or spoiled hundreds of bags of coffee, 14 tons of flour, 200 tons of sugar and all the packs of pasta right from the cardboard packaging.

Scientists now strongly suspect that rats are to blame for the extinction of dinosaurs: they could well have sucked out the contents of laid eggs, thereby ending the glorious line of ancient reptiles. However, this is only a version, and it is not at all necessary to believe it.

Rat.

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Grooming

They constantly need to comb their white fur, and they also need to be washed constantly. To comb the rodent, use a toothbrush, and be sure to have a soft one. While combing, you will have to hold the rodent with your thumbs and forefingers.

If you find yellowness in your pet's fur, then this is a reason to worry. It is possible that your rat is sick and is unable to care for itself.

Important! You should not risk the animal's psyche if you decide to clean the fur by washing it in a basin. You can simply wet cotton pads and wipe your pet's fur

After the procedure, you need to wipe the rodent dry.

Place the cage with the animal away from direct sunlight, as white rats are afraid of bright sunlight.

Varieties

Thanks to the great imagination of genetic engineers and breeders, there is a wide variety of colors of white and black rodents.

The uniform color of a standard ornamental animal is usually black with white spots behind the ears or gray. You can also find brown, chocolate shades with admixtures of white.

As for eye color, there are many variations here too. There are strange individuals with one red and one yellow eye, for example. But more often their color is the same.

Red eyes in albino rats are caused by a lack of protein color, and the color of the coat is associated with the lack of melanin in the animal's body, which is responsible for pigmentation. Although not all white individuals will necessarily have a red color, which is so unpleasant for many. The white rat with black eyes is also often found in pet stores.

Black rodents look very advantageous due to their silky coat and yellow eyes.

What determines the lifespan of a rodent?

An inexperienced breeder may cross-breed sick animals and pass on undesirable traits to the baby rat, such as an inherited health condition, along with a certain color or coat pattern.

The optimal age for purchasing pet rats is about 6 weeks. Look for a healthy rat with shiny fur and lively eyes. Healthy rodents should also be active and inquisitive.

The rat you choose should not be sneezing, have a runny nose or red eyes. And you should make sure that the rat's droppings are dark and hard.

Rat nutrition throughout life.

A rich diet for your pet rat is a guarantee of a long and happy life. Make sure she eats food specifically made for rats, and be aware of which human foods are safe to eat as rodent treats and which are toxic.

Dreams and dies from stress

Researchers say rats dream. They giggle when tickled. They grind their teeth with pleasure when they are stroked - just like cats purr. They are able to express pleasure and happiness on their faces. Believe it or not.

They even tell miracles about trained rats: they can supposedly drink tea decorously at a common table, serve slippers, stand on guard with a “gun” - a sliver of wood behind their backs. And drop dead if a child points a toy gun in their direction. Who else would reveal the secret of their training...

Rats are one of the few animals on the planet that can die from psychological pressure. And their fellow species kills them - for example, when a stranger comes to the colony.

This is how it is described: the head of the colony circles around his victim, raising his fur and snapping his teeth. The guest lies without getting up and breathing intermittently. The aggressor walks around the victim - and she dies from stress after a few difficult hours.

Rat.

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What to feed

Black and white rats are practically omnivores, so you won’t have any trouble feeding your pet correctly, but you still need to remember the basic rules. A rat eats about 40 grams of food per day. Decorative animals need to be fed in the morning and evening.

It is forbidden:

• Pickled
• Salty
• Sweet
• Spicy
• Carbonated

Can:

• Balanced dry food
• Porridges and cereals

Rules:

• Try not to overdo the meat and don't feed it raw.
• Pasyuk loves to sharpen his teeth, so you can add chicken bones to his diet.
• Don't feed too fatty foods.
• Add special vitamin complexes to the albino diet, which is especially important in winter.

If you want to pamper your albino, buy him some nuts, but avoid foods like raw potatoes, rhubarb, cabbage, green bananas, blue cheese and beans.

Sources

• https://apest.ru/krysy/vse-o-krysah/kak-vidyat-krysy/
• https://petse.ru/gryizun/myish_krys/belaya-krysa.html
• https://www.vetpost.ru/veterinarnye-stati/myshinye/dekorativnye-krysy/obychnye-krysy.php

Dossier

Rat.

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Full name: Norway rat (gray), black rat, Bosavi and others.

Nicknames. Pasyuk, kurako, shchur.

Signs. Unevenly gray (“agouti”), sometimes with reddish spots, black, white, mottled.

Special signs. Hairless tail, poor eyesight.

Place of residence: planet Earth.

Character: persistent.

Intelligence: above average.

Suspected: in the death of dinosaurs.

Accused of : causing death by negligence of 25 million people in the 14th century alone; theft of someone else's property by an organized group on an especially large scale; destruction or damage to someone else's property, resulting in particularly grave consequences.