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Chimpanzees tend to pee when others in their radical do , in a phenomenon scientists have dub " contagious urination . "
Because group of masses often go to the bath together too , and chimpanzees are our ' closest living relatives , this societal behavior could be traced back to our common ascendant , researchers say .
Contagious urination was seen among chimps at the Kumamoto Sanctuary in Japan. Researchers think it could help reinforce social bonds among the group.
" In humans , we know that our determination to urinate is influenced by societal contexts that head us to urinate simultaneously with others , and that this coinciding micturition could also further further social soldering , " study co - authorShinya Yamamoto , a wildlife researcher at Kyoto University , told Live Science in an email . " Our study with chimpanzees understandably shows that they share some similarities in this phenomenon , suggesting the mysterious evolutionary bloodline of contagious urination . "
The team adjudicate to learn the behaviour after noticing that a grouping of chimpanzees at a zoo tended to piss at about the same prison term , and wondered whether it could be similar to catching yawning , which has been watch over inother primatesandwolves .
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The scientists found social ranking impacted contagious peeing, with lower ranking members more likely to pee when others did.
For the bailiwick , publish Monday ( Jan. 20 ) in the journalCurrent Biology , researchers observed 20 chimpanzees in incarceration at the Kumamoto Sanctuary in Japan for more than 600 hours .
They found that when one chimpanzee in the grouping peed , others were more likely to adopt . The researcher read the number of urinations that occurred within 60 moment of one another , and then compared these information with randomized computer simulations . The written report found that this catching micturition behavior increased with physical proximity , so chimpanzees seeing another chimp stuffy to them piss were more likely to comply suit .
societal social status also influenced this behavior : Chimpanzees with gloomy ascendancy rank were more probable to pee when others were peeing . Social closeness , measure by clip in close proximity and grooming with another Pan troglodytes , had no effect on the peeing phenomenon — unlike with social yawning , which increase insocially stuffy pairs .
Contagious micturition could be of import to social radical cohesiveness , coordination or reinforcing societal bonds , the researcher said .
The doings could exist to encourage " state - matching , " where Pan troglodytes improve group cohesion by all being in a similar state , study atomic number 27 - authorEna Onishi , a wildlife investigator at Kyoto University , assure Live Science in an email . The conduct could also reinforce social connections .
Another possibility is that multiple Pan troglodytes pass water in a single locating can deter or confuse predator , by trim back the risk of being tracked through disperse water odors .
While no similar studies have yet been transmit on chimpanzees in the wilderness , some research worker have noted similar behaviors in wild population , Onishi say . The research worker are also rummy about whether other mintage show this contagious urination behavior .
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" We are greatly influenced by the presence of others , even in mundane body process , " Onishi say . " For example , in both chimpanzees and human beings , behaviors like oscitance , walking , rhythmical tapping , and even pupil size are known to be transmissible . "
Studying contagious urination could help oneself scientists sympathize the behavior of humans ' common ancestors with chimp , and the origin of the social custom in humans , Onishi order . "
