Abstract: To elucidate the molecular mechanisms of red-green color vision in mammals, we have cloned and sequenced the red and green opsin cDNAs of cat (Felis catus), horse (Equus caballus), gray squirrel (Sciurus carolinensis), white-tailed deer (Odocoileus virginianus), and guinea pig (Cavia porcellus). These opsins were expressed in COS1 cells and reconstituted with 11-cis-retinal. The purified visual pigments of the cat, horse, squirrel, deer, and guinea pig have lambdamax values at 553, 545, 532, 531, and 516 nm, respectively, which are precise to within +/-1 nm. We also regenerated the “true” red pigment of goldfish (Carassius auratus), which has a lambdamax value at 559 +/- 4 nm. Multiple linear regression analyses show that S180A, H197Y, Y277F, T285A, and A308S shift the lambdamax values of the red and green pigments in mammals toward blue by 7, 28, 7, 15, and 16 nm, respectively, and the reverse amino acid changes toward red by the same extents. The additive effects of these amino acid changes fully explain the red-green color vision in a wide range of mammalian species, goldfish, American chameleon (Anolis carolinensis), and pigeon (Columba livia).

Abstract: This paper describes how man can enter the social hierarchy of the horse by mimicking the behaviour and stance it uses to establish dominance. A herd is organised according to a dominance hierarchy established by means of ritualised conflict. Dominance relationships are formed through these confrontations: one horse gains the dominant role and others identify themselves as subordinates. This study was conducted using five females of the Haflinger breed, totally unaccustomed to human contact, from a free-range breeding farm. The study methods were based on the three elements fundamental to the equilibrium of the herd: flight, herd instinct and hierarchy. The trainer-horse relationship was established in three phases: retreat, approach and association. At the end of the training sessions, all of the horses were able to respond correctly to the trainer. These observations suggest that it is possible to manage unhandled horses without coercion by mimicking their behaviour patterns.

Abstract: Management of grazed grasslands for production and/or conservation objectives requires a thorough understanding of the choices of feeding sites by herbivores, and of the biological processes involved. Most models of the feeding strategies of herbivores are based on the principle that optimising the intake of energy (or some nutrient) is the primary goal of foragers but other selective forces, such as parasitism, could be important. Gastrointestinal parasites (including cyathostome nematodes) have powerful effects on the fitness of herbivores and may act as a major selection pressure favouring host behaviour that reduces the risk of encountering parasites. Among large herbivores, horses have perhaps the most marked tendency to select particular feeding sites within grasslands. We test here: (1) whether horses select feeding patches with relatively low parasite densities and (2) if their choice is affected by their parasite load. We used 10 two-year old saddle-horses and three periods. In the first period, the horses were under natural parasitism which varied strongly among individuals; in the second period they were all dewormed, and in the third, a sub-set of the horses was experimentally infected with cyathostome larvae. Ninety-eight percent of the infective larvae in the pasture were found <1 m from faeces. The main determinant of the choice of feeding patch by horses was the availability of patches of different parasite risk and grass height. Controlling for availability, the horses used tall grasses (>16 cm) less than expected, whether the grass was contaminated or not, and they selected for short patches >1 m from faeces, where the risk of encountering parasites was low. These results suggest that selection of feeding sites by horses is driven by an interaction between their nutritional and anti-parasite strategies: the horses avoid the patches of tall grass which are generally of low quality and areas contaminated by parasite larvae which leads them to prefer the patches of short grass far from faeces. The parasite status of the horses at the time of the experiment had no effect on their feeding choices. However, before concluding that the challenge by cyathostomes has no effect on the selection of feeding sites in horses, it will be necessary to test whether the history of parasitism of the individuals, rather than the current status, is important.

Abstract: Anecdotal evidence from horse owners and handlers suggests the existence of breed typical behaviour and personality in horses. This is further supported by current research on heritability of personality characteristics in a range of species. The Horse Personality Questionnaire (HPQ) is a 25-item rating method that has previously been shown to be reliable for the assessment of personality in horses. Principal component analysis on HPQ data has identified six underlying personality components in horses. These are Dominance, Anxiousness, Excitability, Protection, Sociability and Inquisitiveness. Using the HPQ a survey of 1223 horses of eight different breeds was completed. Data were analysed to explore any differences in personality between breeds across the six personality components. Breed differences in personality were identified, and it was noted that variability between breeds varied between personality components. Anxiousness and Excitability showed the most variation between breeds, whilst Dominance and Protection showed the least variance. The results identified breed typical personalities that were comparable to results from previous studies as well as anecdotal evidence provided by the popular equine literature. The results are discussed in terms of the potential selection pressures that may have resulted in these differences.

Abstract: Horses have been considered to rely on human gesticular cues (McKinley and Sambrook 2000, Anim Cogn 3:13-22; and recently Maros et al. 2008, Anim Cogn 11:457-466), however large variability among individuals tested in two-ways object choice tasks was found. Part of the horses in those studies (40 and 26 %, respectively) even failed to pass adequately through the training session which preceded the testing phase and served to learn a horse to carry out a task. Therefore, we alternated the experimental design designed by McKinley and Sambrook (reduced number of testing trials to 10 per horse to keep its attention, applied just one, a dynamic-sustained pointing cue with touching the bucket, etc.), and tested an effect of training method, sex, age, and learning on proportion of correct choices. We hypothesised, that horses trained by “traditional” method (TTM) will get lower score than those experienced with “horsemanship-based” methods (HTM), being characterized by closer and more frequent human-horse contact and also extended exercising “from the ground” with frequent using of arms cues. Despite simplification of the methods, only about 60 % of tested horses passed through the training phase (i.e., learned to come to and upturn the bucket with hidden treat). Successful completion of training phase was reached regardless of age or sex of a horse, but by the training method; HTM horses ran better compared to TTM ones. No significant effect of age, sex, or learning (i.e., trial order within all 10), and training method as well was found on proportion of correct trials in the testing phase. Horses made a correct choice in more than 70% of trials. Individual scores ranged from 50 to 100 %. In conclusion, horses showed high level of comprehension of human pointing gesture, regardless of their sex or age. No effects of training method or learning process within a test suggest low impact of handling and learning on the level of comprehension at least of the most vivid human pointing gesture. Horses trained by methods based on “natural human-horse communication” did enhance cooperation with people.