Kalimantans orangutans (Pongo pygmaeus) can infect each other with the scratching — just as people start to yawn when others yawn. It found Dutch biologists, who for three months followed by nine adult individuals living in captivity. It turned out that contagious scratching common among hostile individuals in the group and more likely to happen in a tense social situation. Article published in American Journal of Primatology.
Social animals often tend to copy the behavior of relatives: this helps to strengthen ties within the group, to improve the chances of survival, and partly to indicate that the species is empathy or the rudiments — that is, the ability to assess the status of the other. Sometimes such copying is an involuntary or even contagious. Bright and very common example is yawning to catch her not only humans, but other primates as well as dogs (however, the infectiousness of yawning other character — at least, with empathy it is not connected).
Another common contagious behavior — scratching (it is, for example, is spread among rodents), but it is not studied in as much detail as yawning. Mariska Kret (Mariska Kret) of Leiden University and colleagues decided to examine a contagious behavior among kalimantans orangutans. For three months (February to may) they followed nine adult orangutans living in the open-air zoo for primates. Scientists recorded all cases of contagious behavior — yawning and scratching — between individuals, within a field of view of each other (up to 10 meters).
For all time of observations scientists have been unable to collect sufficient data to study contagious yawning among orangutans, so they came to the conclusion that this form of behaviour is rarely seen and is not copied. Cases of carding was quite a lot — 597.
Scientists have found that orangutans are much more likely to itch if if they scratched another orangutan (p < 0.01). Contagious scratching was observed approximately three times more often than single, when orangutans each other do not see, and infect animals scratching each other in the first fifteen minutes.
The frequency of infectious carding depended on the situation, which was observed in two animals and their relationships with each other (how much do they spend time together and how friendly the relate to each other). So, the most contagious (p < 0.001) were carding among hostile individuals in a tense situation, which, for example, could end the fight.
People have contagious behavior is more common among relatives — and in fact is an indicator of empathy. Have kalimantans orangutans, apparently, it’s different. Scratching for them — is an indicator of tension, so what itch they are most often in the presence of other individuals — is not surprising. The infectiousness of carding, in turn, can also be an indicator of stress — but in response to that other, unfriendly individual is stressed.
Contagious can be not only the behavior of relatives, but also their emotional state, and it is observed not only among people. Last year, for example, biologists have foundthat crows when decisions are guided by the reactions of their relatives in a similar situation and avoid any action, if they see that another bird is upset.