Beavers use their nose to assess enemy
Beavers use smell to detect when intruders could be a threat, scientists say. For territorial animals, including beavers, “own” a territory ensures access to food, mates and nest sites. Defense struggles that territory may involve causing injury or death.
But how does an animal decides whether to take on an opponent or not, it was not clear. The new study by Helga Tinnesand and colleagues at Telemark University College in Norway found that secretions from the anal glands of beavers contain information on age and social position that helps others beavers measure their level of response to the perceived threat.
Beavers are monogamous rodents, highly territorial with a territory generally consists of a dominant partner in a relationship long term and their offspring. Offspring often left to find their own mates and territories at the age of two and aggressive encounters are common at this time.
Beavers use secretions from anal glands to mark their territory and this has been found to contain a variety of information, such as animal species, subspecies, gender, individuality and kinship.
The researchers hypothesized that information about social status and age or body size can also be contained in the secretions of the male beaver anal glands. This would allow landowners established to accurately assess the level of threat posed by an intruder.
To see if this might be the case, the anal glands secretions were sampled from a land owner and one of his sons, with the child being well aged 2-7 or a year old.
The researchers placed the samples in the territories of other beavers to smell away from each other so that the beaver can detect both at the same time. This allows an accurate assessment of the anal gland secretions which shows the resident beavers showed the most interest in.
Tinnes and he and his colleagues found that residents spent more time beavers sniffing anal gland secretions of older children and yearlings than their parents.
They also showed a stronger physical response to the essence of the older children.
The authors said that this is because the older children who are sexually mature, they are more likely to engage in a physical confrontation for a territory.
The authors concluded that “resident territorial beavers
showed the strongest response to children subordinate territorial higher, suggesting that ranks largest territorial threat.
These results indicate that territorym owners can be identified by smell. “The study was published in the journal Behavioral Ecology and Sociobiology Springer.