The practical ramifications of cheating.
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80 15-min tests using toys were carried out with 4 juvenile chimpanzees who, to obtain the toys, used 4 strategies: (1) taking by force, (2) snatching and fleeing, (3) begging, (4) hysterics. Sharing toys was a normal strategy of high-ranking animals. Begging and hysterics were mainly used in contacts with the latters. A strong negative correlation was found between hysterics and friendly behaviour.
29 male Wistar rats had been individually trained pressing the bar and receiving the rewards in the box with the feeder-cup and the bar attached to the opposite walls. Constant pairs of rats were formed. Behavior of rats in pairs was observed during 100 sessions in the same box. As a rule, one of the rats performed most of the bar pressings ("a worker") while its partner received the rewards without "working" ("a parasite"). It was possible to classify rats in four groups by their behavior, i. e. "parasites", "working", rats which changed their behavior from "working" for "parasitic" type and vice versa in the course of the experiment, and rats from the pairs where both partners extinguished bar pressing reflex near to zero level. Correlation was shown between behavioral type of rats in paired experiment and individual typological characteristics of fear reaction to different stimuli. Tests of open field behaviour, reaction of choice between the burrow and illuminated area, and emotional resonance were used for testing fear reaction.
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Our ambivalence toward competition can be traced to an unspoken preference for certain types of competition which give us an advantage over the types we value less. Four types are defined (a) pure (same rules, same objectives), (b) collaborative (same rules, shared objective), (c) market share (different rules, same objectives), and (d) market growth (different rules, value added orientation). The defining characteristics of the four types of competition are respectively: needing a referee, arguing over the spoils, differentiation and substitutability, and customer focus. Dentistry has features of all four types of competition, thus making it difficult to have a meaningful discussion or frame a coherent policy on this topic.
Many farms using teat-based systems for supplying milk for calves provide only one or a small number of teats for a group of calves, but no previous research has addressed how competition for teats affects calf behavior or milk intake. The aim of this study was to determine how restricted access to teats affects calf competitive behavior, meal-based feeding patterns, and milk intake. Female calves (n=15) were divided into 5 groups of 3 calves each and fed with a teat-to-calf ratio that varied daily from 1:3 to 4:3 using a switchback design. Feeding behavior was recorded by scoring the time and duration of each sucking event. We defined meals using the frequency distribution of log intervals between visits to the teat and identified the within-meal and between-meal distributions intersection points. Three classes of intervals were identified based on the intersection points of the distributions: 1) intervals <2 min, representing small breaks away from the teat within a meal; 2) intervals >41 min, providing an objective definition of a new meal; and 3) an intermediate distribution of intervals from 2 to 41 min could be included in either of the other 2 classes. Meal number showed no significant decrease with decreasing teat number. However, total time on the teat decreased from 40.2 to 32.7 (+/-2.6) min/d, and milk consumption declined from 14.0 to 11.4 (+/-0.8) L/d as teat number declined from 4 to 1. In addition, competitive interactions became more frequent when teat access was reduced; the number of times calves displaced one another from a teat increased from 18 to 41 (+/-5) times/d when teat number decreased from 4 to 1. In conclusion, reduced access to teats increases competitive interactions, decreases feeding time and decreases milk intake by group-housed calves.
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This paper explores the well-known overlap of anxiety and depressive symptoms in mood and anxiety disorders. We suggest that the regulation of both negative and positive affects has served important adaptive functions (especially for coping with threats, losses, failures and defeats), and that in some contexts both affect systems require regulation at the same time (e.g. increased anxiety coupled with low positive affect). Here we will focus on how low positive and high negative affect in the individual experiencing losses and defeats regulates their competitive and acquisitive behaviors and in some cases may prevent, de-escalate, and possibly terminate on-going agonistic (hierarchical) encounters. When high negative affect (anxiety) and low positive affect (depression) fail to fulfill their adaptive roles, they tend to persist and often intensify. This may lead each affect control system to stimulate specific types of anxiety and depressive disorders, exhibiting features reminiscent of the original adaptive function of the behavior. Furthermore, as these different systems tend to operate in a synchronous fashion, the psychiatric syndromes they generate are often comorbid.
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Sperm competition involves competition between the gametes of two or more males of a species for fertilization of a given set of ova. Sperm competition is widespread among mammals, as in many other groups of vertebrates. Effects of sexual selection, via sperm competition, upon the evolution of reproductive physiology and behavior are much better understood in invertebrates (and especially in insects) than is the case for mammals. However, if the reproductive organs of male mammals are viewed as an integrated system for production and delivery of spermatozoa (and accessory glandular secretions) to females, then it is logical to assume that sperm competition might influence the evolution of all parts of the system, as well as associated physiological mechanisms (e.g., testicular endocrinology) and behavior (e.g., copulatory patterns). Here we analyze and review relationships between mating systems, relative testes sizes and sperm morphology, phallic morphology, circulating testosterone levels and sexual behavior in male mammals.
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The effect of competition at feeding on specific categories of growing-finishing pigs was studied in order to provide an explanation for the increased variation in performance within pens previously seen in highly competitive feeding environments. Individual feed intake and feeding behavior, performance, and health were compared for relatively small, medium, and large pigs in pens of 16. Pens contained either one or two dry feeders during a period of ad libitum eating followed by a period of restricted feeding. Computerized feeders that registered the time and amount of feed consumed by each individual were used. Seven replicate groups on each of the two treatments (a total of 224 pigs) were studied. In the pens with only one feeder, the small pigs ate less (P < 0.05) and tended to have a lower daily weight gain (P < 0.10) than the small pigs in pens with two feeders. However, they had a better feed conversion efficiency (P < 0.05). The small pigs also had a different eating pattern. A considerably larger part of their daily feed intake was consumed during the nighttime hours (P < 0.001) when only one feeder was available rather than two feeders. The large pigs ate more during the restricted period (P < 0.01) and had a lower carcass meat percentage (P < 0.05) in the pens with one feeder. Some differences in feeding behavior between the two levels of competition were seen for all categories of pigs. No difference in health was observed between pigs in the one- and two-feeder pens for any size category of pigs. In conclusion, the inability of the small pigs to get access to feed in combination with overeating by the largest individuals caused the variation in performance seen within pens with a high level of competition at feeding (one feeder for 16 pigs). From a welfare point of view, feeding systems causing a high level of competition may be detrimental when considering all individual pigs in pens, even when it is possible to achieve acceptable production results on average.