the smell of predators

It turns out that the identification of the predator by the prey is instinctive by identifying the smell of the predator's secretions, especially the smell of urine

During the period when rumors and sightings of tigers began to arrive (69-70) we looked for verifications of the rumors, one of the first verifications were footprints and excavations where there were remains of secretions. Since we did not know the signs, it took some time before the diggings and tracks were identified as belonging to a tiger, the one who recognized the signs immediately was my dog ​​- Che.

Sometimes I would walk in the streams of the Judean desert with Che, a large wolf-dog (German shepherd), on one of the walks I noticed that Che, who was usually a happy hero, became frightened, his tail between his legs, whined weakly and clung to my legs, only later I tied The appearance of fear if the urine pits dug by a tiger, the typical smell of the pits could be easily smelled, the link to the tiger ….

Later we learned about the preferences of tigers for preying on jackals in the wild... and domestic animal predation... dogs and cats. We thought then that the identity of the predator that causes fear in the prey is ingrained in the brain of the prey as a heredity? Over the years, it has become clear that many predators recognize their predators and predators in general, based on the smell of the secretions, which causes them to flee. Now part of the detection mechanism becomes clear.

The identification of the predator by the prey is instinctive by identifying the smell of the predator's secretions, especially the smell of urine. Stephen Liberles Stephen Liberles and colleagues from Harvard Medical School in Cambridge, Massachusetts collected urine samples from various animals in zoos, including herbivores - prey and cats - predators.

The urine samples were tested and analyzed in an attempt to find out how predators recognize the danger. In a study published in: Proceedings of the National Academy of Science, the team was able to identify the chemical components in the urine and among them the chemical that causes the predators to flee. In the past they have already been identified as micelles that allow the prey to identify a known predator, but this is the first time that "genetic proof" has been identified that allows the animal to locate and identify a predator by force, even if it has never met it.

The researchers began analyzing odor receptors from a mysterious group that was discovered in 2001 and was called trace amine-associated receptors (TAARs). The receptors are found in most vertebrates in varying numbers, mice have 15 receptors, rats 17, people... . Only 6 KKA receptors

Despite the discovery of the receptors, there is not much information about the chemicals that bind to them, the researchers discovered that one group in the receptor family - to which the name KKA4 was given - is activated by the presence of schooner (cat) urine. A concentration of the schooner's urine is sold to gardeners to keep away rodents. The researchers identified and extracted the active molecule: 2-phenylethylamine. (hereafter Phenyl)

After extracting and identifying the molecule and in order to test its presence in the urine of other animals, the researchers collected urine samples from 38 species of animals in zoos. They collected samples from carnivores - lions, snow leopards, jaguars, servals and others, and samples from herbivores - zebra, giraffe, cows, such as Also samples from domestic cats, rodents and... man.

The urine sample showed the different concentrations of phenyl, where the highest levels were in the urine of lions, tigers and servals, concentrations that were 3000 times higher than those found in the urine of herbivores. The researchers assume that the phenyl molecule is a by-product of breaking down/digesting proteins from meat.
To clarify the role of phenyl, the researchers tested the reaction of mice and rats, when there were several drops of phenyl in the field, the rodents avoided approaching, on the other hand, when the phenyl was separated (with the help of an enzyme) from the lion's secretions, the rodents were fearless. The study proved that the phenyl molecule binds to the KKA killers that control the instinctive behavior of animals.

The KKA receptors are located in the roof of the nose in a tissue called vomeronasal
and is part of the epithelium, a tissue that degenerated in humans during evolution, therefore the smell of carnivore urine does not cause fear either.

(On the contrary, there is the extraction of urine material that is used to produce perfumes) To understand the effect of phenyl, the researchers continue and check which brain circuit the receptor activates. As for me now, after many years I understand how and why Che (the dog) who had never met a tiger was startled and afraid when he smelled its presence.

for information about the study