Das ohnehin berüchtigte Schmähwort „Rabenmutter“ müssen wir fortan verbannen aus jeder ernsthaften Unterhaltung. Denn Raben sind ganz anders, als wir dachten.
Für wissenschaftsfeindliche Konservative und Religionsanhänger kommt es noch schlimmer. Der von ihnen gerne beanspruchte Status einer „Krone der Schöpfung“ bröckelt weiter. Auch die Empathie ist kein Alleinstellungsmerkmal des Menschen. Bei Raben ist das nun auch nachgewiesen.
Das sind doch mal schöne Neuigkeiten. Aber stimmt das auch zweifelsfrei? Stellen wir es in der Diskussion auf den Prüfstand.
by „GrrlScientist“, scienceblogs.com
Humans have long tried to distinguish themselves from other animals on the basis of characters that are perceived to be unique, such as tool design and use, planning for the future and the seemingly „human“ capacity for empathy. But one by one, these „unique“ characters are found to be shared with other animals. For example, early research shows that making and using tools is shared with our closest relatives, chimpanzees and bonobos. Since we have a shared evolutionary ancestry, this is not terribly surprising. But when a distantly related animal, such as the New Caledonian Crow, Corvus moneduloides, demonstrates that they also are very capable tool-makers and users [DOI: 10.1126/science.1073433], evolutionary biologists sat up and took note. As if that wasn’t enough, once again, another feature of human „uniqueness“ is being called into question because new research has documented what many bird watchers have known for decades; ravens apparently console their friends after an aggressive conflict with a flockmate.
This is interesting because for a bystander — a flock member, in this case — to console the victim of an aggressive conflict, the individual must first recognize that the victim is distressed and then must act appropriately to alleviate that distress, a complex behavior that requires sensitivity to the emotional needs of others — a trait previously attributed only to humans. Of course after deciding that only humans have this special ability, research has since found that our closest relatives, chimpanzees and bonobos also „console“ victims of conflict [DOI: 10.1073/pnas.0804141105], but researchers haven’t looked closely at many species.
As bird watchers will tell you, many birds are also highly social and very intelligent, two traits that might be prerequisites for empathy. Although very little is known about empathy in birds, there is some tantalizing evidence that it exists. For example, a recent study of Greylag Geese, Anser anser, found that flock members who observed a conflict involving either their partner or a family member experienced an increase in heart rate (a measure of distress) — consistent with an empathic response [DOI: 10.1098/rspb.2008.0146]. Another study, this time in Rooks, Corvus frugilegus, shows that members of breeding pairs perform affiliation behaviors following conflicts, suggesting that pair-bonded individuals may actually be consoling their partner when s/he is distressed [DOI: 10.1016/j.cub.2006.11.025].
This evidence is certainly intriguing, but what happens in young birds that have not yet formed a pair bond? Do they form empathetic „friendships“? To answer this question, a team of researchers at the University of Vienna, Orlaith Fraser, a postdoc, and her co-author, Thomas Bugnyar, a teaching fellow, decided to investigate further. They chose to study the Common Raven, Corvus corax. Like the Rook, the Common Raven is another typical member of the corvid family in that they have complex and long-lived social relationships, and their craftiness and intelligence are legendary — characters that are associated with the capacity to show empathy. Further, ravens are large birds that do not breed until they are between 3-10 years of age, so they are natural choices to study a complex social behavior in birds.
To do this work, Drs. Fraser and Bugnyar removed 13 Common Raven nestlings from four nests (two were zoo bird nests, the other two were wild raven nests) and hand-raised them. After fledging, the young birds were housed together in a large outdoor aviary at the Konrad Lorenz Research Station in Austria in the company of an adult male and female raven who were not related to any of the hand-reared birds. The aviary was made to look as natural as possible, and included trees and other plants, tree trunks and branches, pools of water and stones, and the ravens were given plenty of food and water. (Sadly, the „naturalness“ of this enclosure also led to the deaths of two of the young birds who were killed by predators during the course of this study).