Povinelli DJ, Nelson KE, & Boysen ST. (1992). Comprehension of role reversal in chimpanzees: evidence of empathy? Anim. Behav., 43, 633.
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Dart, A. J., Snyder, J. R., Pascoe, J. R., Meagher, D. M., & Wilson, W. D. (1992). Prepurchase evaluation of horses: 134 cases (1988-1990). J Am Vet Med Assoc, 201(7), 1061–1067.
Abstract: To quantify some components of prepurchase evaluations in horses, records from 134 evaluations performed during a 2-year period were reviewed and the outcome was determined via telephone follow-up interview. Sixty-two percent of the prepurchase evaluations had been performed at the clinic and 38% had been performed in the field by the ambulatory service. All evaluations included physical and lameness examinations, whereas radiography (49%), endoscopy (15%), nerve blocking (5%), transrectal palpation (3%), hematologic analysis (2%), electrocardiography (2%), drug testing for analgesic agents (2%), and ultrasonography of the flexor tendons (1%) were not always performed. Fifty-nine percent of horses evaluated at the clinic were radiographed, compared with 33% of horses evaluated in the field (P less than 0.05). Thirty-seven percent of horses evaluated were judged serviceable for their intended use. Thirty-five percent of horses evaluated at the clinic were assessed to be serviceable, compared with 41% of those evaluated in the field (P less than 0.05). Horses used for pleasure riding (48%) tended to be considered serviceable more often than horses used for more athletic endeavors (3-day eventing, 33%; hunter/jumper, 24%; show, 31%; dressage, 30%). The most common basis for finding a horse unserviceable was lameness (88%).(ABSTRACT TRUNCATED AT 250 WORDS)
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Gutierrez Rincon, J. A., Vives Turco, J., Muro Martinez, I., & Casas Vaque, I. (1992). A comparative study of the metabolic effort expended by horse riders during a jumping competition. Br J Sports Med, 26(1), 33–35.
Abstract: The three main Olympic horse riding disciplines are dressage, jumping, and three-day eventing (including dressage, cross country and jumping). In the jumping discipline (obstacle race), the 'team' (horse rider) is judged under the different conditions that might take place in a varied run. The horse is expected to show power and ability; the rider must show riding skill and good physical condition. However, the different conditions encountered by the rider during competition (duration of event, continuous isometric working level, especially in the inferior trunk, lead us to consider the need for a rider to develop different metabolic pathways to meet the high energy requirements of the competition.
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Steinhoff, H. J., Schrader, J., & Schlitter, J. (1992). Temperature-jump studies and polarized absorption spectroscopy of methemoglobin-thiocyanate single crystals. Biochim Biophys Acta, 1121(3), 269–278.
Abstract: Association equilibria and association kinetics of the thiocyanate binding reaction to methemoglobin in single crystals and solution are studied using temperature-jump technique and polarized absorption spectroscopy. Different kinetic constants are found for the reaction in solution and crystal phase for the alpha- and beta-subunits of the methemoglobin tetramer. The reduction of the reactivity of the alpha- and beta-subunits in crystalline phase is 6-fold and 2.4-fold, respectively, compared to the values found in solution. The intramolecular binding reaction of the N epsilon of the distal histidine E7 which is observed in methemoglobin in solution cannot be detected in single crystals. Our results suggest that crystallization of hemoglobin has little influence on small-scale structural fluctuations which are necessary for ligands to get to the binding sites and large-scale structural motions are suppressed.
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Detmer, D. (1992). Response: of pigs and primitive notions. Between Species, 8(4), 203–208.
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Rubenstein, D. I., & Hack, M. A. (1992). Horse signals: The sounds and scents of fury. Evol. Ecol., 6(3), 254–260.
Abstract: During contests animals typically exchange information about fighting ability. Among feral horses these signals involve olfactory or acoustical elements and each type can effectively terminate contests before physical contact becomes necessary. Dung transplant experiments show that for stallions, irrespective of rank, olfactory signals such as dung sniffing encode information about familiarity suggesting that such signals can be used as signatures. As such they can provide indirect information about fighting ability as long as opponents associate identity with past performance. Play-back experiments, however, show that vocalizations, such as squeals, directly provide information about status regardless of stallion familiarity. Sonographs reveal that squeals of dominants are longer than those of subordinates and that only those of dominants have at their onset high-frequency components.
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Dugatkin, L. A. (1992). Tendency to inspect predators predicts mortality risk in the guppy (Poecilia reticulata). Behav. Ecol., 3(2), 124–127.
Abstract: Although predator inspection behavior in fishes has become a model system for examining game theoretical strategies such as Tit for Tat, the direct costs of inspection behavior have not been quantified. To begin quantifying such costs, I conducted an experiment that examined mortality due to predation as a function of predator inspection in the guppy (Poecilia reticulata). Before being subjected to a “survivorship” experiment, guppies were assayed for their tendency to inspect a predator. Groups were then composed of six guppies that differed in their tendency to inspect. These groups were placed into a pool containing a predator, and survivorship of guppies with different inspection tendencies was noted 36 and 60 h later. Results indicate that individuals that display high degrees of inspection behavior suffer greater mortality than their noninspecting shoalmates.
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Anderson, J. R., Fornasieri, I., Ludes, E., & Roeder, J. - J. (1992). Social processes and innovative behaviour in changing groups of lemur fulvus. Behav. Process., 27(2), 101–112.
Abstract: A group of brown lemurs was presented with one or two baited food-boxes requiring a specific type of motor response in order to be opened. Subsequently, four groups containing different combinations of experienced individuals from the original group and naive individuals were tested. Solutions to the problem and access to the food were recorded and considered in relation to social factors. In the original group, two adult males learned to open the boxes, with one male increasingly preventing the other from approaching. In the second group, with the subordinate male and certain females removed, the dominant male tolerated successful performances by a juvenile female. Group 3 consisted of three passive female participants from the original group and a naive female; one of the three original females now became the sole box-opener. The introduction of the subordinate male from the original group into the all-female group led to a sharing of box-opening by this subject and the skilled female. In the final group, intense aggression toward the skilled female by a new, naive adult male resulted in two previously passive females succeeding on some occasions. In lemurs, at least some `scroungers' appear able to learn to perform a new act when the social context permits.
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Keiper, R., & Receveur, H. (1992). Social interactions of free-ranging Przewalski horses in semi-reserves in the Netherlands. Appl. Anim. Behav. Sci., 33(4), 303–318.
Abstract: Social interactions were recorded in two bands of free-ranging Przewalski horses living on large (greater than 30 ha) pastures in the Netherlands. The average number of aggressive interactions per hour was 8.86 at Lelystad and 10.36 at Noorderheide. The most common aggressive interactions were lower intensity, lower cost displacements (17.2% of all aggressive acts at Lelystad, 13.2% at Noorderheide), threats to bite (42.3% and 40.7%, respectively) and threats to kick (15.4% and 23.9%, respectively). Analysis of aggression revealed that a clear, linear dominance hierarchy was present in each band. For each band there was a positive and highly significant correlation between the age of a horse and its rank in the hierarchy. In each band, the stallion was not the highest ranked horse. Non-agonistic behaviors exceeded the number of agonistic interactions (1253 vs. 558 for Lelystad; 1257 vs. 995 at Noorderheide). There was a negative correlation between the rank of a horse in the dominance hierarchy and the number of non-agonistic behaviors displayed. The group displaying the highest number of non-agonistic interactions were foals (48.9% of total non-agonistic behaviors at Lelystad; 51.1% at Noorderheide). The non-agonistic/agonistic ratio was greater than 1 for yearlings and the band stallion, as was also the case for foals, but was less than 1 for males.
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Timney, B., & Keil, K. (1992). Visual acuity in the horse. Vis. Res., 32(12), 2289–2293.
Abstract: We assessed the ease with which horses could learn visual discriminations and measured their resolution acuity. We trained three horses to press their noses against one of two large wooden panels to receive a small food reward. Following training on a series of two-choice discrimination tasks, resolution acuity was measured. Although there was some variability between animals, the best acuity obtained was 23.3 c deg-1. Within the margin of error imposed by limited anatomical data, the obtained values are consistent with predictions based on retinal ganglion cell density estimates and posterior nodal distance/axial length ratios. They suggest that the resolution acuity of the horse is limited by ganglion cell density in the temporal portion of the narrow visual streak.
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