How sensitive is a dog's sense of smell? The sensitivity of a person's sense of smell is underestimated.

Neuroscientist: The human sense of smell is underestimated compared to other mammals... Dogs do have more olfactory receptors in their noses than human noses, but for certain flavors, such as ethyl acetate, the main smell of bananas, the human nose is more sensitive.
aristotle said that people's sense of smell is not good, and Darwin believed that smell was not of much use to civilized humans.
we have long thought that humans have a bad sense of smell, but this is a misunderstanding.
now, a new scientific analysis challenges this view, pointing out that human smell is not only underestimated, but no worse than dogs and rodents.
, a neuroscientist at Rutgers University in the United States, came to this surprising conclusion in a paper that he spent 14 years studying the olfactory system.
," he said, "For a long time, no one has questioned this view, even those who have studied smell throughout their lives."
fact, humans don't smell as well as other animals, such as dogs and rodents.
McGann said he was wary of the "big myth" after trying to apply rodent experiments to humans.
he said: "There are two flavors that mice can't distinguish, and humans don't, but the opposite is true."
the human olfactory system is incredible.
" McGann holds Paul Broca, a 19th-century brain surgeon, responsible for the idea that humans have a bad sense of smell, which he has written into the scientific literature.
Broca points out that human olfactory balls (the brain regions that process odor detection) are smaller than dogs and mice.
this finding is in line with Freud's view that human sexual repression is due to the degradation of the sense of smell.
in a paper published recently in The Science, McGann points out that humans have bigger olfactory balls in absolute terms than any mammal, and another study suggests that the absolute number of olfactory neurons is highly consistent among mammals.
we looked at the human brain in medical school, and we put the human olfactory ball together with the mice, and the human race was significantly larger, " he said.
" McGann continues to deconstruct other arguments that support the idea that humans have a bad sense of smell.
humans have about 1,000 odor receptor genes, while mice have 1,100, which seems to indicate that mice have a better sense of smell.
, however, another study showed that the number of olfactory genes was not closely related to the sense of smell.
also found that cows have 2,000 of these genes, far more than dogs.
these are encoded by different odors in the nose, which can detect different volatile chemicals in the air.
thought that only a third of human olfactory genes work, and the rest seem to be evolutionary relics.
, however, recent studies suggest that the number may be higher.
McGann says even the constant sniffing of some animals can go wrong.
When a mouse comes into contact with a new smell, it exhibits "rapid exploratory sniffing, but when a mouse hears a strange sound or sees something strange, it reacts similarly, and sniffing means curiosity to some extent."
" McGann acknowledges that dogs have higher concentrations of olfactory receptors in their noses, which may explain why they can also smell at low odor concentrations.
, however, even dogs have weaknesses.
humans are more sensitive to certain flavors, such as ethyl acetate, the main smell of bananas, which may be because the discovery of ripe fruit is more important to human ancestors than to dogs.
this is not the first paper to argue that human smell is underestimated.
published last year found that humans can distinguish between trillions of odors (although this is controversial), and an earlier study showed that humans were able to track odors in grasslands.
McGann said he had tried it, saying: "I used to lie on the grass in the park tracking the smell and you could try it in the yard, which was very impressive.
," said Matthew Cobb, a professor of zoology at the University of Manchester.
said: "We have always thought that humans have a bad sense of smell, and McGann is looking for evidence for this, but the evidence is not sufficient."
this will change the course I'm going to take next year, " he said.
", there are also doubts about it.
Alexandra Horowitz, a scientist at Barnard College in New York who has been studying dogs' sense of smell, points out that dogs can track smells, find drugs, detect ovarian cancer through plasma, and humans can only notice if the smell in the subway is bad and if someone is cooking at home.
" she said: "There are a lot of olfactory experts, such as spice makers or animal trackers, who point out that we can do better if we pay attention, but not at the level of dogs.
"