Animals release specific odors into the air when they are stressed, and these odors increase anxiety in conspecifics. These alarm odors or alarm pheromones appear to be important signals that are evolutionarily conserved because they are released by a variety of mammalian species, including rats, deer, cattle, swine, and humans.
A research team led by the Professor Yuji Mori*, Associate Professor Yukari Takeuchi, and Assistant Professor Yasushi Kiyokawa in the Graduate School of Agricultural and Life Sciences at the University of Tokyo has identified a mixture of 4-methylpentanal and hexanal in the rat alarm odor and demonstrated that this mixture is a pheromone increases anxiety in other rats. These compounds were isolated from the many substances released from the rat perianal region, and while they had no effect individually, in combination they increased anxiety in rats.
The results of this study identifying this pheromone could aid further research on rat pheromones, and enhance our understanding of chemical communication in mammals. In addition, these findings could help us develop new technologies using pheromones to control mammal pests.
* Professor Mori passed away on 17 September 2014.
Source: University of Tokyo