It is said that certain animals have vision or sense of smell work better than we do – or that they can pick up what we did not catch, such as magnetic fields. How do we know this, asks the correspondent of BBC Earth.
Everyone knows that some animals amazingly developed sense organs.
The dogs are much better than us, running nose, and cats see in complete darkness when a person without the flashlight can not do.
Some animals may even feel the things that we did the report does not give – for example, ultraviolet radiation Earth’s magnetic field.
Stories about the incredible sensory abilities of animals are constantly appearing in the media. But how do we know about them? We can not ask a fish what it sees.
Romeynes waited while his dog is not distracted by another dog, and then quickly sped, winding along the way
To find out, it takes a lot of ingenuity. Here are some ways to imagine what it is – to see through the eyes of fish or sniffing dog’s nose.
You should start with the most simple: you can watch the animals in the wild.
To take even larger birds of prey, scavengers such as vultures.
They can see the decaying carcass in the bushes providing good camouflage, and even from a distance of several kilometers.
We conclude: the vultures are able to to recognize the fine details of objects.
Canine scent
If we need more precise information, it is possible to conduct behavioral experiments. One of the first such experiments took place at the end of the XIX century, its author – English biologist George Romeynes.
One day, he went for a walk with his dog in London Regents Park. In Romeynesa it was clearly mischievous mood, and he decided to test the ability of the dog.
Romeynes waited while his dog is not distracted by another dog, and then quickly sped, winding on the run. When the dog came back, she realized that the owner left, and immediately began sniffing the ground.
Guided by its scent, the dog went in his footsteps, who brought her straight to wait for her owner.
Anatomy of the senses can tell a lot about how they function
This spontaneous experiment gives a good idea of how prominent canine sense of smell and how useful it can be.
Thanks to the following experiments George Romeynes found that dogs can detect certain odors from long distance, even when there were other, more strong odors.
His observation is still regularly cited forensic experts, including FBI agents.
These different ears
The next step – the study of the sense organs of the animal.
The Anatomy of the senses can tell a lot about how they function.
Take, for example, human ears. Each of them has a cochlea: a small spiral structure containing thousands of specialized nerve cells that are able to pick up sounds.
spiral shape of the cochlea gives us an idea of what is how it works: it is especially good picks quiet, low sounds.
In 2006, the researchers simulated the passage of sound in a spiral, and found that the low-frequency amplified.
The antennae of insects allows them to smell, taste, touch, hear, determine the temperature and feel the breeze
With this fix quiet, low-frequency sound of a man is easier than if the cochlea was not.
Similarly, the mustache (or antenna) of insects allows them to smell, taste, touch, hear, determine the temperature and feel the breeze.
In the course of the evolution of each of these feelings on the antennae were relevant elements, which are visible under the microscope.
Daniel Robert from Bristol University (UK) has been studying the order, insects use their antennae to hear. In 2001, he teamed up with Martin Gopfertom investigated the antennae of mosquitoes.
Mosquitoes use antennae to pick up audible vibration – including in situations where there is close to the opposite sex. Their antennae – 15-16 thousand auditory cells, explains Robert.
From the sound-proof capsule, Robert and Gopfert sent a very thin laser beam antenna mosquito. To their surprise, they found that even in silence antenna slightly vibrated at a frequency of approximately 440-450 Hz. So, auditory cells are almost always on the move.
No one’s ever seen anything like this
When you start a sound wave, auditory cells start to move in sync with it, amplifying the sound. As a result, the mosquito begins to hear better sound.
Cells “added weak pulse required them frequency, – says Daniel Robert. – In some cases it makes it possible to amplify the sound of 10 or even 100 times”.
Robert used similar methodology to study the microscopic ears of grasshoppers, located on their front legs below the knee.
Having microtomography these tiny ears, Robert and his colleagues found that they act within the “lever system” that responds to vibrations caused by sound. Again, this increases the effect of sound waves.
“No one’s ever seen anything like it,” – says the researcher. – Do some deep-sea fish in the retina has only sticks “
With the passage of vibrations through the ear of a grasshopper, they fall into a small hole filled with liquid and cover sensory neurons that detect sound.
Daniel Robert was able to find out with the help of a laser fixing micro-movements, and dynamics, make sounds for insects.
“The high frequency of the sound, which we translate, create powerful vibration at the contact – such as our cochlea – he explains. – Bass passed on to other cells below it. “In the human ear, similar processes take place.
Who else sees?
To learn more, we can refer not only to the anatomy, but also to the characteristics of the individual cells of the senses.
In some deep-sea fish in the retina has only sticks, unlike the person – in our retina presented and rods and cones.
This gives us an idea of how they see. Cones are needed for color vision , so the lack of fish speaks to their inability to recognize colors.
That’s how we found out that the vision of dogs is not adapted for the perception of color information.
The representatives of the cat family – and wild lions and domestic cats – are unable to taste sweet
There are only two kinds of cones, and a man three. As a result, they feature yellow and blue colors, but do not see the red and green colors.
A man uses a stick to see in dim light.
At the deep-sea fish are “incredible size” says Ron Douglas of City University London (UK).
This allows them to catch as much as possible available to them light and see little in the dark.
Smell and taste
A similar approach can be applied to smell and taste.
So, the researchers counted the number of olfactory receptors in dog noses. In bloodhound their more than 200 million, and a man – only 5-6 million. This is yet another confirmation of the fact that a dog’s sense of smell is superior to our.
Another study were carried out in 2006 showed that the cat language is not the taste buds that respond to sweet.
It turns out that members of the cat family – from wild lions and tigers to home Murok – unable to feel the sweetness of food.
In human terms the sense of smell in fruit flies can be called limited
It is not clear why it happened, but the cat’s known for its carnivorous habits, so sweet flavors in their diet do not occur too often.
On the other hand, fruit flies have olfactory receptors, which perfectly capture the fruity smell, but do not catch virtually anything else.
According to human standards their sense of smell has been limited, but it is well adapted to their needs.
Touch the ability of the animals are not exhausted their hearing, sight and smell. You can also keep track of how sensory signals pass through the animal’s nervous system to the brain.
To do this, scientists are using electrophysiological testing. In the eye or the brain of the animal is placed a tiny electrode that detects minute impulses from the senses.
One of the key issues – how well the animal sees rapid flashes of light. According to Ron Douglas thus determined by its ability to capture movement.
They’re chickens, feel as if living in a disco
The human eye can see up to 50 light flashes per second. If the frequency of outbreaks is increasing, man thinks that included a constant light. For example, fluorescent lights are flashing more than 100 times per second, but we can not grasp this.
Other animals are more sensitive to flickering light. For example, some chickens are able to see about 100 light flashes per second, so the use of fluorescent light in their cells is problematic.
“They feel as if living in a disco – says Douglas. – Obviously, there is a violation of animal rights”.
Genes and Brain
In addition, there is also the brain itself.
“Genes determine how the animal developed sense of smell, sight, hearing and taste”
Functional magnetic resonance imaging (fMRI) allows you to see when activated by a particular part of the brain. To do this, tracked changes in blood flow and oxygen levels in the blood.
The body aims to ensure a flow of oxygenated blood to the neurons, which are involved senses.
That’s how we learned that in the dog the brain has specific areas that process complex information, which is associated with the smell.
In 2015, a study was published according to which the activity of the dog brain is different depending on whether a familiar or an unfamiliar human scent scented dog.
Finally, we must examine the animal’s DNA.
All aspects of feelings of an animal from their devices to the number of receptors and activity of the brain, ultimately determined by its genes.
The genes determine how the animal developed sense of smell, sight, hearing and taste.
Some animals can pick up things that we basically can not feel
This means that we can learn a lot about the sensory organs of the animal, relying solely on the information about his DNA.
In 2014, researchers have carefully studied the genomes of 13 species animals, trying to find the genes that are responsible for the sense of smell.
At the African elephants were more genes related to smell than any other animal, studied at the time.
We do not know what specifically affects a large part of these two thousand genes, but the actual figure suggests that elephant noses unusually well equipped.
One more thing. Until now, we were interested in the study of the sensory abilities of animals, which has the man.
However, some animals can detect things that we basically can not feel.
It turns out that some creatures are able to see the form of light, invisible to the human eye.
is inaccessible to man
For example, many animals can see ultraviolet light with a wavelength in the range of 10 to 400 nanometers.
We can find out, see whether the animal is born with one or another wavelength if the check passes if it through the lens of his eyes.
bees is a kind of landing lights
The lens of a healthy person is blocking ultraviolet radiation, so we do not see. However, a variety of wildlife ultraviolet light helps to see in dim light, says Ron Douglas.
Some surfaces reflect only ultraviolet light, causing the majority of people do not see them, unlike animals.
For example, there are flower petals with stripes reflecting ultraviolet material, attracting pollinating insects.
“Honeybees see the marks that indicate her location of nectar, – says Douglas. – For the bees is a kind of boarding lights “.
Bees do follow this “nectar signs” by which they collect pollen and can then pollinate other flowers. It turns out, the system works like a flower and bees.
In animals, there is still more strange sensory abilities, but scientists have found a way to learn and.
For example, we know that migratory birds sense the magnetic field of the Earth. data-link=”http://www.bbc.com/russian/science/2015/11/151119_vert_ear_how_we_know_what_animals_see_hear_smell”>Откуда
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