小仓鸮通过分享来互相帮助 This is Scientific American ' s 60-second Science . I ' m Jason Goldman . Robin Hood famously stole from the rich and gave to the poor .
Young , newly hatched barn owls do something similar . On average , barn owls raise six chicks at once-and sometimes as many as nine .
But they don ' t all hatch at the same time , which means the older owlets are generally larger and healthier than their younger brothers and sisters . As long as the little owls remain in the nest , they ' re completely dependent on their parents for food .
The problem is that the small rodents that they eat can ' t be split up . So when Mom or Dad returns to the nest to feed their offspring , only one chick can eat a time .
In many bird species , the oldest would simply outcompete the youngest , but barn owls are different . Turns out the older , healthier birds sometimes donate their meals to their hungrier siblings .
Adults in other animals species share their food . " It ' s mainly observed when males want to reproduce with females , so there ( are ) many ( exchanges ) of food .
Or in primates , there ( are ) many ( exchanges ) of food and grooming but only in adults ." Evolutionary biologist Pauline Ducouret from the University of Lausanne in Switzerland .
" And in chicks , it is really rarely observed . So it ' s quite impressive that in this species , there are so many cooperative behaviors ." She and her team wanted to know how this unique behavior evolved .
It could be explained by the direct benefits gained through cooperation , such as trading food for grooming . Or it could be explained by the indirect benefits gained from helping others that share your genetic heritage-also known as kin selection .
They found that the answer was both . Younger birds groomed older ones more often than older ones groomed the youngsters . And in return , the older birds fed their younger siblings .
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