Different levels of complexity in the play-fighting by muroid rodents appear to result from different levels of intensity of attack and defense

1989 ◽  
Vol 15 (4) ◽  
pp. 297-310 ◽  
Author(s):  
Sergio M. Pellis ◽  
Vivien C. Pellis ◽  
Donald A. Dewsbury
Author(s):  
Kelly L. Kraus ◽  
Vivien C. Pellis ◽  
Sergio M. Pellis

Play fighting in many species involves partners competing to bite one another while avoiding being bitten. Species can differ in the body targets that are bitten and the tactics used to attack and defend those targets. However, even closely related species that attack and defend the same body target using the same tactics can differ markedly in how much the competitiveness of such interactions is mitigated by cooperation. A degree of cooperation is necessary to ensure that some turn-taking between the roles of attacker and defender occurs, as this is critical in preventing play fighting from escalating into serious fighting. In the present study, the dyadic play fighting of captive troops of 4 closely related species of Old World monkeys, 2 each from 2 genera of Papio and Mandrillus, was analyzed. All 4 species have a comparable social organization, are large bodied with considerable sexual dimorphism, and are mostly terrestrial. In all species, the target of biting is the same – the area encompassing the upper arm, shoulder, and side of the neck – and they have the same tactics of attack and defense. However, the Papio species exhibit more cooperation in their play than do the Mandrillus species, with the former using tactics that make biting easier to attain and that facilitate close bodily contact. It is possible that species differences in how rigidly dominance relationships are maintained are expressed in the play of juveniles by altering the balance between competition and cooperation.


Author(s):  
B. T. Himmler ◽  
S. M. Himmler ◽  
R. Stryjek ◽  
K. Modlińska ◽  
W. Pisula ◽  
...  

Play fighting in rats involves attack and defense of the nape. To protect the nape, rats use a variety of defensive tactics, with different strains having specific preferences. Targeting of the nape is established before weaning and defense matures over the course of the week preceding and the week proceeding weaning. Thus, it is possible that experience from engaging in immature forms of play is needed to consolidate the nape as the playful target and for the development of the juvenile-typical pattern of defense. Two experiments were conducted to evaluate this possibility. For the first experiment, male rats were reared over the week post-weaning in either pairs or alone, and their play tested with unfamiliar partners when juveniles (31-34 days). For the second experiment, during the week preceding weaning, male and female rats were placed into one of three conditions: (1) with the mother and no peers, (2) with same-sex siblings but no mother or (3) with both the mother and same-sex siblings. The subjects were tested in same-sex, same-condition pairs when juveniles (31-34 days). Rats from all conditions, in both experiments, attacked the nape during play fighting and developed the same juvenile-typical patterns of playful defense. This suggests that the experience of peer-peer play in the peri-weaning period is not necessary for the development of the attack and defense components of juvenile-typical play.


Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.


Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.


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