Pointing and holding up objects in order to attract attention has so far only been observed in humans and human's closest living relatives, the great apes. Scientists have now provided the first evidence that common ravens (Corvus corax) also use so-called deictic gestures in order to test the interest of a potential partner or to strengthen an alreadyexisting bond.

A deictic gesture is a gesture that points at some place. It aims at requesting the addressee's attention on that place in order to refer either to the place itself or to an object, person, or concrete or abstract event located in or linked to that location. From early childhood on, children frequently use distinct gestures to draw the attention of adults to external objects. Deictic gestures such as "pointing" ("Look here") and "holding up of objects" ("Take this") are used by children for the first time at the age of 9 to 12 months prior to producing their first spoken words. Scientists believe that such gestures are based on relatively complex intelligence abilities and represent the starting point for the use of symbols and therefore also human language. Deictic gestures are thus milestones in the development of human speech. Scientists feel that deictic gestures represent an extremely rare form of communication evolutionarily. These gestures have so far been suggested as confined to primates only. However, according to the latest research, such behavior is not restricted to humans and great apes. For 2 years, researchers investigated the nonvocal behavior of individually marked members of a wild raven community in the Cumberland Wildlife Park Gr�nau in Upper Austria. A scientific research center is located in the 148-acre park, which is surrounded by the Tote Gebirge Mountain Range and home to many of Austria's native wildlife species. The researchers observed that ravens use their beaks in a similar way to hands to show and offer objects such as moss, stones, and twigs. These distinct gestures were predominantly aimed at partners of the opposite sex and resulted in frequent orientation of recipients to the object and the signalers. Subsequently, the ravens interacted with each other, for example, by example billing or joint manipulation of the object. Ravens are songbirds belonging to the corvid family that includes crows and magpies, and they surpass most of the other avian species in terms of intelligence. Their scores on various intelligence tests are similarly high as those of great apes. Ravens in particular can be characterized by complex intra-pair communication, a relatively long-time period taken to form bonds, and a relatively high degree of cooperation between partners. This new study shows that differentiated gestures have especially evolved in species with a high degree of collaborative abilities. Gesture studies in the past have too often focused on communicative skills of primates only. The mystery of the origins of human language, scientists feel, can be more easily solved if the bigger picture is studied while also considering the complexity of the communication systems of other animal groups. Common ravens make many different kinds of calls for communication. They often seem to be speaking or mimicking the sounds of other animals because they are capable of making so many different kinds of sounds. They also make alarm calls, advertise their territories by calling, and make comforting sounds. The common raven is a striking, all-black bird, 22 to 27 inches from beak to tail. Ornithologists believe that their all-black plumage helps them absorb and retain heat in high altitudes and northern latitudes. Features that distinguish them from crows are their large size, heavy bill, shaggy throat hackles, long-fingered wing tips and long wedgeshaped tail.

0 comments:

Post a Comment