Most of the animals are bestowed upon by the almighty to sniff immensely the environmental conditions, situation & more importantly the probable dangers that can emanate from a particular place. Like wise the human beings are also equipped with the quality of smelling danger but to a less extent that of animals. So the next time if someone tells that his nose sniffs danger in the air, that might be literally true and more interestingly the danger odour might be coming from you & you only.
At the tip of the noses of mammals, including human beings, is a ball of nerve cells known as the Gruenberg Ganglion, named after Hans Gruenberg, the scientist who described the structure in mice in 1973. But that time he thought that it was just a nerve ending. But only in last few years after scientists devised strains of mice that glow green under fluorescent light, did they deduce that the ganglion is a compound of the olfactory system. But they still did not know what the ganglion smelled.
In the Journal of Science, the researchers at the University of Lausanne in Switzerland report that they figured it out, at least for the green -glowing mice. All sort of organisms, including plants, insects and mammals, release alarm pheromones when they sense danger; the pheromones waft through the air to warn others. Very little is known about the alarm pheromones of mammals other than that they exist. Scientist are still in research phase to know more about the phenomenon.
Researchers have not yet identified the compounds and also they do not know where in the body the pheromones are produced. Nevertheless, the Lausanne scientists could collect the phenomenons by simply stressing mice and sucking up the air around them. At least in the experiment on mice when exposed to the danger- scented air, it was found that they froze in their tracks. So more research is required on gruenberg ganglion which seems to be responsible for smelling danger. If more facts revealed, the human beings can also predict the danger by sniffing in the air.