Zeitschrift fur Tierpsychologie最新文献

Forms of aggression, their situational motivations and frequencies in Thomson's gazelle were investigated to elucidate the multiple functions of aggressive behavior as well as quantitative differences in encounters with opponents of different sex, age, and social classes. The study was conducted in the Serengeti National Park (Tanzania) where the gazelle population is estimated to total 600 000. Within three years, 4016 agonistic encounters were recorded and analyzed. Besides the confirmation of its conventionally recognized functions in territoriality, etc., the great role of intraspecific aggression in the coordination of group activities appears to be of special importance.

In the Biville chalk cliff area the Herring gulls nest both in slope and ground colonies and on cliff ledges. Like the Kittiwake (CULLEN 1957), the cliff-nesting pairs still accept other chicks after the 1st week of life. Gulls in slope and ground colonies, however, attack those chicks older than 4 days in close proximity to their nests (TINBERGEN 1936).

By replacing parts of the neural plate (prospective medulla oblongata) of Triturus vulgaris by neural ectoderm of Xenopus laevis larval chimaeras were obtained, which showed donorlike rhythmical movements of distinct parts of the visceral musculature according to the place of implantation. Especially the branchial region with its external gills showed rhythmical movements and is the special object of this investigation.

Nine different reactions of unconditioned agonistic behavior of golden hamsters (Mesocricetus auratus Waterhouse) which could be elicited by an air blow (UCS) were classically conditioned at a sound of a xylophone (tone g), a previously neutral stimulus. Tone g (CS) was paired with UCS for a different number of trials/day. In all animals exposed to over 20 pairings/day components of the agonistic behavior were brought under the control of CS, but it was not possible to predict which one of the agonistic reactions would appear. Most of the animals generalized and also showed conditioned reactions (CR) when presenting tone c' instead of tone g. When utilizing a differential conditioning procedure the animals learned to discriminate between the different tones. Extinction of CR at tone g was reached after an individually different number of trials.

The possibility of learning time intervals was examined. 7 male BDE-rats (70 days old at the beginning of the experiments) were trained (shock avoidance learning) in a modified test chamber to learn bar-pressing only in distinguished time periods (LD 12 : 12). In a second part of the experiment it was examined with 5 rats what effect an extension of the light phase has. The results show that there is a possibility of learning time intervals and of maintaining this behaviour under these specific conditions of training.

Play behavior was studied in a captive group of Siberian ibex at the Chicago Zoological Park. The hypothesis that physical training effects were at least partially responsible for the evolution of play in this species was tested by noting the amounts of play which occurred on flat and on sloped surfaces. The kids showed a clear preference for play on sloped terrain, even though this choice resulted in considerably greater risks. The danger involved in highly active locomotor play performed on steeply sloped areas is presumably outweighed by the physical training benefit for an adult life spent moving in precipitious areas.

Wild-coloured Zebra Finch nestlings with fully developed mouth markings were compared with white mutants, which lack the markings, with respect to the ability of these markings to release the feeding response of both wild-coloured and white parents. In more than 80 nestlings, the wild-coloured ones proved to have a higher survival rate, to grow faster, to be given more food, and to have piority to the first feedings in the day. Within the colour groups greater relative age was as advantageous as mouth markings were between groups.

Between the siblings of a family of greylag geese (Anser anser L.) a rank order is established by fighting during the first days after hatching, and also by other, more complex interactions. The position of each goose in the rank order can be defined by three groups of behaviour patterns (aggressive behaviour, "greetings", escape responses). A clear-cut ranking relation between two individuals is a prerequisite for their close cohesion. The survival function of rank order lies in diminishing the intensity and frequency of agonistic interactions, in diminishing social stress situations and in guaranteeing the close family cohesion.

As part of a study of sexual behavior in 6 species of closely related and often sympatric cockroaches, interspecific interactions among the various species were examined. To some degree males of nearly all species court females of a second species. Females almost always rejected these courtship attempts. Experimental evidence indicates that the volatile female sex pheromone of each species is attractive to males of most of the other species. Rejection of heterospecific males appears to be due to species specific male pheromones. These pheromones also appear to mediate the formation of homospecific clusters of courting males in time or space.

Mouse-eared bats leave their young at their sleeping place during the nocturnal hunting flight. The young wait for their mothers' return crowded together in small groups. It is examined whether mother and offspring recognize each other upon the mother's return. It is experimentally shown that each recognizes the other by smell and ultrasonic sound.