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Fisher, J., & Hinde, R. A. (1994). The opening of milk bottles by birds. British Birds, (42), 347–357.
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Byrne R.W. (1994). The evolution of intelligence. In P.J.B. Slater and T.R. Halliday (Ed.), Behaviour and Evolution (pp. 223–265). Cambridge,UK: Cambridge University Press.
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Bekoff, M. (1994). Cognitive Ethology and the Treatment of Non-Human Animals: How Mati'ers of Mind Inform Mati'ers of Welfare. Animal Welfare, 3, 75–96.
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Wilson, S. D., Clark, A. B., Coleman, K., & Dearstyne, T. (1994). Shyness and boldness in humans and other animals. Trends. Ecol. Evol, 9(11), 442–446.
Abstract: The shy-bold continuum is a fundamental axis of behavioral variation in humans and at least some other species, but its taxonomic distribution and evolutionary implications are unknown. Models of optimal risk, density- or frequency-dependent selection, and phenotypic plasticity can provide a theoretical framework for understanding shyness and boldness as a product of natural selection. We sketch this framework and review the few empirical studies of shyness and boldness in natural populations. The study of shyness and boldness adds an interesting new dimension to behavioral ecology by focusing on the nature of continuous behavioral variation that exists within the familiar categories of age, sex and size.
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Irvine, C. H. G., & Alexander, S. L. (1994). Factors affecting the circadian rhythm in plasma cortisol concentrations in the horse. Domest. Anim. Endocrinol., 11(2), 227–238.
Abstract: In horses, a circadian rhythm in plasma cortisol concentrations has been reported in some but not all studies. When a rhythm occurred, horses were accustomed to a management routine, comprising stabling, feeding and sometimes exercise, which may entrain a circadian pattern. In this work, we monitored plasma cortisol by collecting jugular blood through indwelling cannulae from four groups: 1): 10 untrained, unperturbed mares grazing excess pasture, bled hourly for 26 hr; 2) 4 mares housed in a barn for 48 hr before sampling every 15 min for 20–24 hr; 3) 5 mares placed in an outdoor yard for sampling every 30 min from 0930–2100 hr; and 4) 4 stabled racehorses in training, bled every 30 min from 0730–2000 hr and once the following morning at 0830 hr. Plasma cortisol showed a similarly-timed circadian rhythm (P<0.0001) in all Group 1 horses, with a peak at 0600–0900 hr, and a nadir at 1800–2100 hr. By contrast, cortisol concentrations did not vary with time in either Group 2 or 3. Neither daily mean nor peak cortisol values differed in Group 1 and 2 (i.e. bled for >= 20 hr); however nadir values were higher (P<0.05) in Group 2. In Group 4, cortisol declined (P=0.004) during the sampling period but had returned to initial concentrations the next morning. Values did not differ from those for Group 1, except between 1000 and 1300 hr when cortisol in Group 4 was lower (P<0.05). We conclude that a circadian cortisol rhythm exists in horses in the absence of any known cues imposed by humans. However, this rhythm can be obliterated by the minor perturbation of removing the horse from its accustomed environment. By contrast, the rhythm occurs in trained racehorses, suggesting either that they have adapted to their environment thereby allowing an endogenous rhythm to emerge, or that the rhythm is entrained by their daily routine. These observations highlight the difficulties in determining the cortisol status of a horse, since measurements will be affected by time of day, the occurrence of short-term fluctuations, and how accustomed the horse is to its environment.
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Atock, M. A., & Williams, R. B. (1994). Welfare of competition horses. Rev Sci Tech, 13(1), 217–232.
Abstract: In the large majority of cases and circumstances, horses benefit from their association with man. However, abuse of horses can occur, due to neglect or through the pressures of competition. The welfare of all animals, including competition horses, has become increasingly topical over the past ten years. Equestrian sport is coming under closer public scrutiny due to reports of apparent abuse. The bodies responsible for regulating these sports strenuously endeavour to protect the welfare of horses which compete under their rules and regulations. The Federation Equestre Internationale (FEI: International Equestrian Federation) is the sole authority for all international events in dressage, show-jumping, three-day event, driving, endurance riding and vaulting. The FEI rules illustrate the ways in which the welfare of competing horses is safeguarded.
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(1994). Winter horse care. Journal of Equine Veterinary Science, 14(2), 115–117.
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Chiba, K., Ikai, A., Kawamura-Konishi, Y., & Kihara, H. (1994). Kinetic study on myoglobin refolding monitored by five optical probe stopped-flow methods. Proteins, 19(2), 110–119.
Abstract: The refolding kinetics of horse cyanometmyoglobin induced by concentration jump of urea was investigated by five optical probe stopped-flow methods: absorption at 422 nm, tryptophyl fluorescence at around 340 nm, circular dichroism (CD) at 222 nm, CD at 260 nm, and CD at 422 nm. In the refolding process, we detected three phases with rate constants of > 1 x 10(2) s-1, (4.5-9.3) s-1, and (2-5) x 10(-3) s-1. In the fastest phase, a substantial amount of secondary structure (approximately 40%) is formed within the dead time of the CD stopped-flow apparatus (10.7 ms). The kinetic intermediate populated in the fastest phase is shown to capture a hemindicyanide, suggesting that a “heme pocket precursor” recognized by hemindicyanide must be constructed within the dead time. In the middle phase, most of secondary and tertiary structures, especially around the captured hemindicyanide, have been constructed. In the slowest phase, we detected a minor structural rearrangement accompanying the ligand-exchange reaction in the fifth coordination of ferric iron. We present a possible model for the refolding process of myoglobin in the presence of the heme group.
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Zentall, T. R., & Sherburne, L. M. (1994). Role of differential sample responding in the differential outcomes effect involving delayed matching by pigeons. J Exp Psychol Anim Behav Process, 20(4), 390–401.
Abstract: The role of differential sample responding in the differential outcomes effect was examined. In Experiment 1, we trained pigeons on a one-to-many matching task with differential sample responding required. Differential outcomes were associated with samples and comparisons, with comparisons only, or with neither samples nor comparisons. Slopes of delay functions for trials with pecked versus nonpecked samples suggested use of a single-code-default strategy in the nondifferential-outcomes group but not in the differential-outcomes groups. In Experiment 2, differential sample responding and differential outcomes were manipulated independently. Again, there were significant differences in the relative slopes of the delay functions. Results suggest that differential outcomes exert their effect independently of differential sample responding.
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Zentall, T. R., & Sherburne, L. M. (1994). Transfer of value from S+ to S- in a simultaneous discrimination. J Exp Psychol Anim Behav Process, 20(2), 176–183.
Abstract: Value transfer theory has been proposed to account for transitive inference effects (L. V. Fersen, C. D. L. Wynne, J. D. Delius, & J. E. R. Staddon, 1991), in which following training on 4 simultaneous discriminations (A+B-, B+C-, C+D-, D+E-) pigeons show a preference for B over D. According to this theory, some of the value of reinforcement acquired by each S+ transfers to the S-. In the transitive inference experiment, C (associated with both reward and nonreward) can transfer less value to D than A (associated only with reward) can transfer to B. Support for value transfer theory was demonstrated in 2 experiments in which an S- presented in the context of a stimulus to which responses were always reinforced (S+) was preferred over an S- presented in the context of a stimulus to which responses were sometimes reinforced (S +/-).
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