Discrimination of the threat of direct versus tangential approach to the nest by incubating herring and great black-backed gulls.

Examined the ability of incubating herring (Larus argentatus) and black-backed (L. marinus) gulls to discriminate between people walking directly toward their nests and those merely walking tangentially by their nests. Study groups varied in their habitat (open vs vegetated) and previous exposure to human disturbance. Herring gulls responded when the experimenter (E) was at a greater distance from the nest if the approach was directly toward the nest with the person looking at the incubating bird, and gulls in disturbed areas responded sooner than birds in undisturbed areas. In habitats with low visibility (dense bush cover), the gulls could not see E early enough to show different responses to the 2 treatments. Black-backed gulls nested only in undisturbed areas, and only slight differences were evident in the distance at which they left the nest. However, they called more when E was approaching the nest directly. In this study, gulls habituated to the continual presence of humans by modifying their responses, but even habituated birds continued to reassess the potential danger of a nearby human and perceived subtle differences between a direct and a tangential approach. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nest repair behavior in birds nesting in salt marshes.

Studied 5 species of birds nesting in salt marshes in New Jersey to determine their ability to respond to natural and experimental changes in their nests. Laughing gulls and clapper rails nest in the lowest areas of the marsh, common terns nest in intermediate areas, and herring gulls and mallards nest in high marsh areas. Manipulations of nests included wetting nests and differentially removing nest material. Nests were also observed following a high tide. There were differences in nest repair as a function of species and treatments. Laughing gulls and rails significantly repaired nests under most conditions, herring gulls and common terns repaired nests under some conditions, and mallards never repaired their nests. It is concluded that, generally, species are responsive to nest changes as a function of their nesting location in the marsh. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mouse aggression and the intruder-familiarity effect: Evidence for multiple-factor determination.

Male house mice attack their familiar cagemates less than novel intruders, an effect often attributed to habituation of aggression toward odors emanating from the cagemate. This interpretation is overly simplistic in that the effects of familiarizing preexposure depend additionally on 2 factors. One factor is the aggression-inhibiting odors emanating from the test male that are deposited onto the cagemate by cohabitation. Supporting evidence from 3 experiments with 138 wild mice and 138 laboratory-bred mice show that attack inhibition to the cagemate failed to generalize to noncohabiting same-strain intruders and that eliminating physical contact between S and cagemate during preexposure prevented the usual postexposure decline in aggression. The 2nd factor is nonolfactory social stimuli emanating from the cagemate during aggressive encounters. The same intruder odors that elicited aggression when placed on a socially active mouse elicited only investigation when placed on models. When Ss were preexposed to an intruder's odor while prevented from socially interacting with the intruder, this investigation subsequently declined while aggression paradoxically increased. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of ultrasonic vocalizations emitted by residents during aggressive encounters among rats (Rattus norvegicus).

Determined the extent to which aggressive resident rats emit 40–70-kHz vocalizations and the effect of these signals on intruders. In Exp I, 16 deafened and intact intruder male Long-Evans rats were given 2 encounters with 8 resident Ss. Deafened intruders engaged in a higher duration of immobile or freezing postures than intact Ss. Exp II indicated that the augmentation of freezing found among deafened intruders was not due to an inability to detect ultrasounds made by residents since intruders encountering devocalized resident males showed no reliable differences in specific motor patterns from intruders paired with intact residents. Results demonstrate that 40–70-kHz vocalizations were produced almost entirely by intruding Ss since there were no significant changes in occurrence of these calls when resident males were devocalized. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of ultrasonic vocalizations emitted by intruders during aggressive encounters among rats (Rattus norvegicus).

Determined the ultrasonic vocalizations produced by intruders during aggressive interactions and investigated the role of these signals in agonistic behavior of rats. In Exp I, 7 experienced resident male Long-Evans rats were paired with both devocalized and intact vocalizing naive intruder males (n?=?14). Devocalization of the intruder males resulted in a drastic decrease in 50-kHz vocalizations and the elimination of all 22-kHz vocalizations. This almost total absence of ultrasonic vocalizations was not accompanied by any change in resident aggressive behavior or intruder defensive and submissive behavior. In Exp II, 16 naive intruders were tested with either deafened or intact resident males (n?=?8). Similarly, preventing residents from hearing intruder ultrasounds had no detectable effect on any aggressive behavior. These experiments are not consistent with the correlative evidence that intruder-produced 22-kHz vocalizations inhibit the aggressive behavior of the resident. Results show that most of the ultrasonic vocalizations emitted during aggressive encounters were probably produced by the intruder. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predation, aggression, and activation levels in food-deprived sunfish (Lepomis macrochirus and L. gibbosus): Motivational interactions.

Three experiments investigated the effects of food deprivation on several behavioral categories in a total of 56 bluegill and pumpkinseed sunfish ( Lepomis macrochirus and L. gibbosus, respectively). In Exp I, predatory behavior and general activity were observed under 5 levels of deprivation. For both species, predation measures increased in a similar negatively accelerating manner with increasing deprivation, while activity changed in a more complex fashion. Exp II examined the effects of deprivation on activity in a novel environment and showed that the deprivation effects of Exp I were masked by the response to the new setting. In Exp III, measures of aggression toward intruders of each species were recorded from resident fish of both species under 3 levels of food deprivation. Both species were more aggressive toward conspecifics, and bluegills were more aggressive overall. Aggression was significantly affected by food deprivation, with the effects dependent on the species making up the pair. Theories of motivational summation, generalized drive, and activity-mediated aggression are seen as inadequate to explain the differential effects of hunger on the 3 behavioral categories observed. A dynamic boundary-state model of behavior was, however, found to predict the motivational interactions observed between distinct behavioral control systems. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of tail autotomy on agonistic behaviour in a territorial salamander

Assessment of potentially asymmetrical characters (such as fighting ability and resident advantage) is often important in determining the outcome of agonistic interactions. Loss of body parts, a predator defence mechanism used by many animals, may lead to a reduction in fighting ability and may be easily assessed by competitors. We investigated the influence of tail loss on the expression of agonistic behaviour in the territorial red-backed salamander, Plethodon cinereus. Residents and intruders were matched for body size, and pairs were tested in all combinations of tailed or tailless residents with tailed or tailless intruders. Neither residents nor intruders altered their behaviour based on their own tail condition, but they did alter their behaviour based on the tail condition of their opponents. Intruders showed more aggression or less submission towards tailless residents than towards tailed residents. When contests were between residents and intruders of the same tail condition (both tailed or tailless), intruders were more aggressive towards residents when both were tailless than when both were tailed, indicating that tail loss does not directly hamper aggressive displays. In contests where the asymmetry between residents and intruders was small (based on tail condition and residency status), intruders showed more aggression and less submission than in contests where the asymmetry was large. Residents did not differ in their behaviour for most comparisons. Thus, for intruders, the tail condition of residents is an important determinant of agonistic behaviour displayed in territorial contests. For residents, factors other than tail condition (such as resource value) may be more likely to influence their behaviour. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

Review of The herring gull's world.

Reviews the book "The herring gull's world," by Niko Tinbergen (see record 1955-00376-000). This book summarizes in nontechnical language a large number of observations and experiments by the author and his students on the behavior of herring gulls. Primary emphasis is placed upon social behavior including formation of breeding pairs, establishment and maintenance of a territory, courtship and mating, and rearing of young. The book achieves several objectives very effectively. First, it presents a clearly drawn picture of the behavior of gulls in their natural environment. Second, it illustrates authoritatively a method of analyzing behavior which differs in several important ways from techniques used by American psychologists. Third, the book exemplifies an attitude or philosophy of behavior study quite unlike that of experimental psychologists. The author's enthusiasm for behavior study combines with his long-standing affection for sea gulls to produce an eminently readable, entertaining, and informative volume, the attractiveness of which is enhanced by numerous excellent photographs of gull behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory cues and movement: Stimuli mediating intraspecific aggression in the wild Norway rat.

Established male sibling pairs of laboratory-bred wild rats (R. norvegicus) in enclosures and in 4 experiments observed their aggressive, amicable, and sexual behavior following the introduction of conspecifics. Intact male Ss behaved amicably toward familiar male conspecifics, both aggressively and sexually towards unfamiliar anestrous and estrous female conspecifics, and aggressively toward unfamiliar male conspecifics. Anosmic males exhibited amicable and sexual behavior toward unfamiliar males, but did not initiate aggression toward them. The storing of a member of a resident pair in a cage with or without wood shavings, urine, and feces from a foreign colony did not affect behavior toward him by his cage mate. The storing of a foreign male in the wood shavings, urine, and feces of a colony did not affect behavior of that colony toward him. Cessation of movement on the part of an intruder of either sex inhibited attack, while immobile anesthetized male intruders elicited aggression. When presented simultaneously with moving and anesthetized intruders, resident Ss attacked only the former. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stomach acid secretion in submissive and aggressive rats.

Conducted 4 experiments with 60 female and 162 male Long-Evans rats to determine whether aggressive and submissive behavior are related to either an increase or a decrease in gastric secretion. In Exp I, intruder rats placed in an established male–female colony and attacked by a dominant alpha male secreted less acid than intruders exposed to nonaggressive males and females. In Exp II, intruders exposed to attack and subsequently returned to the encounter site, but protected from physical attack, still demonstrated a gastric hyposecretion. Ss with chronic gastric cannulas in Exp III also revealed an acid inhibition when attacked and later when exposed to, but protected from, attack. Both intruders and attacking males were prepared with gastric cannulas in Exp IV. Both demonstrated secretory inhibition following attack and attack-protected sessions. The inhibitory effect was greater and more persistent for intruders than for aggressive Ss. It is suggested that the inhibition occurring during the attack-protected sessions may have been mediated by some conditioning processes, and other possible associative mechanisms, including a learning model or a direct sensory model, are discussed. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral impairments of lead-injected young herring gulls in nature

Lead is ubiquitous in the environment, and trace amounts enter the food chain and bioaccumulate in organisms high on the food chain. Although lead levels have been examined in a variety of wild species, effects data are usually from laboratory studies. Thus the relevance of effects to survival and fitness are not directly determined. In the field we compared the behavior of lead-injected young herring gulls (Larus argentatus) to the behavior of their control siblings who received an injection with no lead and to chicks from control nests that received no injections. Lead-injected chicks had significantly lower survival rates than all controls. Lead-injected chicks were less healthy than control chicks as measured by begging and walking scores and by the number of times they stumbled when walking. Control chicks had a higher degree of accuracy when pecking at their parents' bills to stimulate feeding compared to the lead-injected chicks. For all chicks, begging and walking scores improved with age. Behavioral deficits measured in the laboratory are homologous with those observed in the field.     

Aggressive behavior in female hamsters: The hormonal basis for fluctuations in female aggressiveness correlated with estrous state.

The frequency and sequencing of aggressive behaviors by naive female hamsters has been found to change during series of brief encounters, probably because of the lack of stable dominance relations. Such initial encounters seem most representative of interactions likely in free-ranging hamsters and have been emphasized in studies of the hormonal mediation of female aggression. The present 4 experiments, conducted with a total of 72 random-bred female hamsters, found that nonestrous females exhibited intense aggression toward conspecifics of either sex. Estrous females were not aggressive and spent much time in lordosis, indicative of sexual receptivity. While oil-injected adrenalectomized-ovariectomized females fought at high levels, comparable with intact nonestrous females, the combination of 17-β-estradiol benzoate and progesterone suppressed fighting completely. In contrast, replacement of estradiol, progesterone, or testosterone propionate individually had no consistent effect. Hypophysectomized females also fought at high levels, indicating that pituitary hormones are not required for vigorous aggression. Further, individual anterior pituitary hormones did not produce marked changes in fighting. Results emphasize the roles of estrogen and progesterone in synchronizing aggression with current reproductive state. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic basis of malignant melanoma]

Visalberghi and Fragaszy [Animal Behaviour 49:1089-1095, 1995] have shown that social influences affect acceptance of novel foods. However, little is known about the temporal course on which such influences act (e.g., for how long they persist and for how many encounters they are effective). To explore this issue, 11 adult tufted capuchins were observed during ten successive encounters with eight unfamiliar foods (phase 1, in which subjects were tested in social or individual condition) and ten more encounters 6 months later (phase 2, in which all subjects were tested in social condition). A total of 680 observational sessions were carried out. Results show that during the first five encounters in phase 1, capuchins ate more when they encountered these foods in the presence of their groupmates than if they encountered them alone. Thereafter, during the second five encounters of phase 1, foods were consumed equivalently whether presented to monkeys socially or individually. In phase 2, the foods were consumed equivalently regardless of the previous circumstance of their presentation (social or alone). In phase 2, consumption was similar to that scored in a previous study for familiar foods [Visalberghi & Fragaszy, Animal Behaviour 49:1089-1095, 1995]. We conclude that 1) foods remain unfamiliar to capuchins only for the first few encounters, 2) social facilitation of consumption of unfamiliar foods is of limited duration, and 3) individuals consumed equivalent amounts of an unfamiliar food when they repeatedly encountered it alone or in the presence of groupmates. These results caution those who interpret similar feeding habits in primate groups as evidence of social influences.     

Dominance in intermale encounters and subsequent sexual success in mice.

In Exp I, when previously isolated male CD-1 mice (n?=?26) were paired and given a female, they fought before beginning to mount, and the more aggressive male ejaculated somewhat more frequently. Males housed together (n?=?26) for several days showed little aggression when jointly given a female, but those that were more aggressive in the home cage clearly ejaculated more frequently. In Exp II, with 144 Ss, males were paired for 4 days after a period of isolation. More aggressive males showed more ejaculations when subsequently tested individually with females, but not when pair members conjointly encountered females. In Exp III, 60 males were paired for several weeks before encountering females. In cases in which home cage dominance was constant, the more aggressive males ejaculated more frequently both when tested individually and when tested as pairs. Findings indicate that success in reproductive behavior in mice is contingent on dominance in intermale aggressive encounters. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Striped Mouse (Rhabdomys pumilio) From the Succulent Karoo, South Africa: A Territorial Group-Living Solitary Forager With Communal Breeding and Helpers at the Nest.

The authors studied the striped mouse (Rhabdomys pumilio) in the semiarid succulent karoo of South Africa. Mice forage alone, but they live in groups that share a common nest. Groups consist of 1 to 4 breeding females, 1 to 2 breeding males, and their offspring of both sexes, which remain in their natal group even after reaching adulthood, participating in territorial defense and nest building without showing signs of reproductive activity. Interactions are typically amicable and take place inside or in front of the nest. In contrast, encounters with mice from other groups are aggressive. Group living in the succulent karoo is possibly due to ecological constraints imposed by habitat saturation because of a year-round stable food supply as well as associated benefits of philopatry. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Urine marking and maternal aggression of wild female mice in relation to anogenital distance at birth

A series of experiments were conducted with wild house mice to verify the effect of intrauterine position on females' anogenital distance at birth (AGD) and to examine the relationships between a female's AGD, used as a bioassay of androgen exposure during fetal life, and her social behavior and reproductive success in adulthood. Experiment 1 showed that cesarean-delivered females that developed in utero between two males (2 M females) have significantly longer AGD's than females positioned between two females (0 M females). We then categorized naturally delivered females shortly after birth as having a long, medium or short AGD. In adulthood, these females were tested for their behavior towards unfamiliar pups, their rate of urine-marking in response to a variety of social stimuli, postpartum aggression and success in protecting their litters in response to male and female intruders. Adult females with different AGD's at birth did not differ either in their behavior toward pups or in their rate of urine marking. Conversely, males housed across a wire mesh partition from a long-AGD female deposited a higher number of urine marks than those exposed to a short-AGD female. When tested after delivering a litter, long-AGD females displayed more tail-rattling (a component of agonistic behavior) towards intruders of both sexes in comparison to short-AGD females. These results are consistent with the hypothesis that females with a long AGD are exposed to higher levels of Testosterone during fetal life than females with a short AGD. Although not related to AGD, other measures of maternal aggression were affected by postpartum day, sex of intruders and a female's infanticidal potential while a virgin.     

Ontogeny of aggressive-sexual behavior between males in lines of Japanese quail (Coturnix coturnix japonica) selected for male mating frequency.

100 male Japanese quail, from lines bidirectionally selected for high and low mating frequency and from a random-bred base population, were observed in an ontogenetic study of aggressive/sexual behavior. Ss were reared in sex-intermingled flocks until 28 days of age, at which time half of the Ss from each line were housed as all-male flocks and half were transferred to individual cages. At 41 days of age, individually caged Ss exhibited mounting behavior to win encounters with other Ss. By 45 days, Ss from the high and control lines exhibited significantly more aggressive sexual behavior than those from the low lines. Line?×?Rearing Experience interactions for mounting behavior at 45 and 56 days of age were due to the individually caged high- and control-line Ss' winning encounters by mounts; those maintained in flocks rarely mounted. Although some low-line Ss won encounters by mounts, the occurrence of this behavior was infrequent. Ss maintained in flocks were placed in individual cages at 57 days of age. When these Ss and those housed in individual cages from 28 days of age were compared at 84 days of age and older, the Line?×?Rearing Experience interaction observed previously disappeared, and only differences among genetic lines were evident. Genetic and rearing experience effects are discussed as influencing agonistic and sexual behaviors. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Female-enhanced aggression in male rats: Effects of genital anesthesia, castration, or preoptic lesions.

Male rats that had cohabited with ovariectomized females for 2 weeks became more aggressive toward male intruders after a novel estrous female had been placed in their home cages for a period of 4 hr on the previous day. No increase in aggression was seen in males exposed to anestrous females. Genital anesthesia did not attenuate the female-enhanced aggression effect. By contrast, no enhancement of aggression was observed in long-term castrated males after 24 hr of exposure to estrous females. Rats with bilateral electrolytic lesions in the medial preoptic area showed a normal female-enhanced aggression effect. The observations that exposure to females facilitates aggression in males subjected to genital anesthesia and in males with preoptic lesions raise the possibility that copulatory cues are not always required for the effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Competitive behavior in male, female, and pseudohermaphroditic female dogs.

Tested 36 male, spayed female, and pseudohermaphroditic female dogs in pairs for competition over a large bone. Pseudohermaphrodites had been exposed to testosterone propionate before and immediately after birth. In equal opportunity (EO) tests, both members of a pair had equal chance to seize the bone. Each EO test was followed by an established possession (EP) test. During an EP test, the loser of the preceding EO test was given possession of the bone before the former winner was returned to the test arena. Every S was tested against all other members of its own and the other groups. Males won 78 of 100 EO tests against normal females but only 61 of 100 against pseudohermaphrodites. Pseudohermaphrodites won 70 of 100 EO tests against normal females. When either normal or pseudohermaphroditic females were given possession of the bone in EP tests they were equally ineffective in defense against male challengers, losing 75 and 71% of their tests, respectively. Both types of females were more successful in defending possession during EP tests against each other. When normal and pseudohermaphroditic females were treated with testosterone, their performance in competition tests was not altered. Androgenic stimulation before and immediately after birth permanently modified the social behavior of pseudohermaphrodites as well as the behavior of males and normal females toward experimental Ss. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dominance between booby nestlings involves winner and loser effects

Two-chick broods of the blue-footed booby, Sula nebouxii, ordinarily exhibit stable dominance-subordinance, with the senior (first-hatched) chick habitually aggressive and the junior one habitually submissive (Nelson 1978, The Sulidae: Gannets and Boobies. London: Oxford University Press). But are both the subordinate and the dominant chick affected in their agonistic tendencies by early social experience? To answer this, we permanently paired subordinate and dominant chicks, 2-3 weeks old, with singletons (chicks lacking experience with a nestmate) by cross-fostering. During the first 4 h after pairing, subordinate chicks were seven times less aggressive than singletons and twice as likely to be submissive; dominant chicks were six times as aggressive as singletons. Although most subordinates consistently lost agonistic encounters during the first 10 days after pairing, the proportion of dominants that won decreased progressively until, by day 6, only about half of dominant chicks were winning. Early social experience has a strong but reversable training effect on both subordinates and dominants. Training as a subordinate showed more persistent effects than training as a dominant, possibly in part because our testing situation perpetuated subordinate training and counteracted dominant training. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.