Sensory Functions of Dogs

Dogs’ sensory abilities are marvelous. Especially its ability to sniff out so many different smells. Whether as a drug-sniffing dog or man trailer, the dog’s nose is valued and used in many areas of our everyday life. However, the dog’s other senses must also be taken into account if you want to understand and experience your dog even more and better.

An Overview of the Sensory Functions of Dogs

Dogs enrich our lives and make them very special. We live closely with them but perceive the environment very differently. The reason for this lies in their senses. Just like humans, they have five senses – but they are developed differently.

See

Dogs are able to recognize even the smallest differences in brightness. The darker the environment, the better dogs can distinguish differences. The tapetum lucidum is responsible for this, among other things, and dogs can enlarge their pupils very much.

Dogs can only see certain shades of color. Because they lack a type of cone in the eye structure, they are unable to see the hue of green. On the other hand, they can see violet, blue, yellow, and white tones particularly well and distinguish them from one another. Colors like red, yellow, orange, or green, on the other hand, cannot really be distinguished by dogs. For example, if you throw a yellow toy onto a green field, your dog won’t be able to see it but will be able to locate it using its other senses.

When it comes to recognizing movement stimuli, however, no one can fool a dog. A dog perceives even the smallest movements, which we humans sometimes do not really recognize. Dogs, on the other hand, cannot recognize motionless objects.

A dog’s vision can deteriorate with age or as a result of illness.

Listen

Dogs can hear much better than humans. The shape of the ears (floppy/stick ears) is irrelevant. They perceive the sound waves in the air. These always arise when particles move in the air. If the sound waves get into the dog’s ear, the eardrum vibrates and the actual hearing process takes its course.

Dogs are able to hear in a frequency range from 20 Hz to 50 kHz. This also explains why they can hear mice underground or literally cough fleas. Nature and its animal world represent an extraordinary background noise for your dog. However, our everyday life is peppered with all kinds of noises that are inconspicuous to us, if not audible at all. But our four-legged friends notice them. Here, for example, energy-saving lamps or the often-used electric toothbrushes should be mentioned. It is an amazing feat for dogs to block out such supposedly disturbing noises and to filter out specific noises from this whole mixture of sound waves.

Too much earwax, mites, an ear infection, or the wrong direction of the wind can lead to a loss of hearing quality. Not to be forgotten: in old age the ability to hear decreases.
Smell
A dog’s ability to smell is indisputably far superior to that of humans. To give you a better idea: Dogs have around 220 million olfactory cells. We humans, on the other hand, are just between about 5 and 10 million.

Dogs are also capable of switching back and forth between normal breathing and sniffing. This means that when the dog breathes, it can direct the airflow through the nasopharynx towards the lungs. When sniffing, i.e. inhaling the scent, the breathing rhythm is different. The four-legged friend can breathe in the air up to 300 times in one minute, directing it to the olfactory mucosa. This always requires sufficient moisture so that the odor particles can be bound and thus analyzed.

Taste

In dogs, the taste receptors are located in the mucous membrane of the tongue. They reside in small clusters called taste buds. The perception of taste is all the more sensitive, the more of these taste buds are present. Dogs have far fewer taste buds than humans. For better comparison: Dogs have around 1700 to 2000 taste buds, while we humans have around 9000.

Dogs have four types of taste buds. They can taste sweet, sweet-fruity, sour, bitter, and savory-spicy (also called “umami”) and distinguish them from each other. This is due to the presence of different taste sensory cells that react to different types of stimuli. The taste of salty things is very weak in dogs.

Touch and Touch

The dog has sensory cells all over its body that react to any kind of touch stimulus. These are touch, pain, and heat-cold receptors. The dog also has such receptors inside the body, i.e. the internal organs and also in the joints. Not only is the dog’s skin very sensitive, but also the protective coat. Each individual hair has nerve fibers at its root, which makes tactile sensitivity possible.

Dogs have what is called sinus hair. Compared to the other body hair, these are longer and sit deeper. They are mainly found on the face of the four-legged friend, around the nose and mouth, as well as over the eyes and on the forehead.

Scattered sinus hairs can also be found distributed on the dog’s body. These are called so-called guide hairs. They also have nerve fibers at their roots, but these are much denser than the rest of the hair. With the sinus hair, dogs can perceive and recognize touch, but just as well air currents.

Dogs are also able to sense and respond to electromagnetic fields with their fur and sinus hair. You can sense the earth’s static magnetic field using different types of receptors.

Our dogs’ senses are very fascinating. They often surprise us with things they perceive and respond to. Training your own sensitivity here can open up a whole new perspective on your own dog.

The Development of the Sensory Abilities of Dogs in Puppy Age

At birth, not all of a dog’s senses are developed, but he can already perceive a variety of stimuli in the womb. Some sense organs develop faster than others. For example, the eyelids change during this time in order to be able to protect the eyeball in particular. In the beginning, the eyelids are only loosely together. They even grow together as the pregnancy progresses. About two weeks after birth, the eyes open bit by bit, and only after several weeks do they reach their full functionality.

The development of hearing also begins much later. Immediately after birth, the ear canals are still closed. Finally, during the third week, they slowly begin to open up. It is astonishing that puppies can still perceive hearing impressions immediately after birth. If there are loud noises in the immediate vicinity, the dog’s head vibrates slightly. These are then transmitted to the hearing organ. The puppy can thus get an impression of this sound. Hearing is fully developed after a few weeks.

The sensation of pain, the sense of balance, and the perception of temperature already develop in the womb. Although they are not yet fully functional there, various receptors are already working.

The Sense Organs

The dog ear

The dog-ear can be divided into three sections, firstly the outer ear. This includes the auricle, the auditory canal, and finally the eardrum. The ear canal is covered with a mucous membrane and, after a vertical piece, turns into a horizontal section. At the end of this horizontal section is the eardrum, a membrane that can vary in size depending on the size of the dog. The vertical section of the ear canal is partially covered with hair.

The second part of the ear is in the middle ear. It is a cavity filled with air. This is where the auditory ossicles are located. This cavity is connected to the pharynx via a tube. With each swallow, this air space is ventilated.

The third section is the inner ear. There is a connection between the cavity and the inner ear with its sensory cells through two openings. This area is also known as the labyrinth. There lies the organ of hearing, which is called the organ of Corti. In addition, the balance organ is also located there.

The dog nose

Smelling is not just smelling for the dog. He has two ways of perceiving smells. On the one hand, of course, over his nose. He breathes in the air with the odor particles. A very well-functioning system of fine vessels that circulate the mucous membrane and glands that provide liquid provides the basis for the easy absorption of the scent molecules from the air. In addition, dogs are able to alternate between breathing and consciously sniffing.

On the other hand, four-legged friends can perceive smells via their mouth-olfactory organ, the vomeronasal organ. Named after its discoverer, this organ is also called Jacobson’s organ. It sits on the palate. It gets the olfactory information from the mouth on the one hand and from the nose on the other. However, only the heavy fragrance particles that come out of the oral cavity are decisive. The particles come from the pheromones, which are excreted through various body fluids. You may have seen the well-known trembling of the jaws and a simultaneous smacking with possible foaming in a male dog. In this case, the male has perceived the scent of a bitch.

The dog eye

The incident light passes through the cornea into the anterior chamber of the eye. The iris located there has the task of regulating the exact amount of light. In the center of the iris is the pupil, a circular opening. This allows the light rays to go further. A reflex controls the extent to which the pupil widens or shrinks. If it is dim, for example, the pupil is set as wide as possible in order to capture as many rays of light as possible. In contrast, the pupil is made narrower so that the photoreceptor cells can be protected in bright light.
In the further course, the light reaches the lens, where the light rays are bundled. With the help of the vitreous body, the light rays are projected onto the retina. Depending on the degree of curvature of the lens, the image may be sharp or less sharp.

Especially when it comes to vision, there are special features in the different breeds, especially as far as the field of vision is concerned. In dogs with a long muzzle, the field of vision is 270 degrees. On the other hand, for dogs with round and flat faces, it is only 220 degrees. For comparison: with us humans, it is just 180 degrees.

Balance

The balance organ is responsible for the balance. It is in the inner ear and is very sensitive. It consists of three tubes. These are curved in a circle and filled with liquid. The tubes are arranged approximately at right angles to each other. This fact makes it possible to realize any rotary movement.