Abstract: 1. Data on plant species foraged, foraging hours, bite rate, bite size and species dry matter (DM) removed per species per bite were collected in tussock grass-forb (Grass-F), forb-tussock grass (Forb-G), Trachydium-forb (Forb), Rhododendron-Cassiope and early successional communities from May to September in a moderately foraged Central Himalayan alpine meadow in order to study the foraging niche characteristics of horses, sheep and goats. 2. The three animals together grazed 30 plant species, of which 20 were grazed by horses, 22 by sheep and 16 by goats. 3. The average foraging hours (5.2-13.2), bites per minute (23-51) and mg DM per bite (59-99) for horses, sheep and goats were significantly different in different communities and months. 4. The foraging search cost, reckoned as distance walked per unit DM eaten, was highest for goats (15.4 km kg$^{-1}$), followed by sheep (8.1 km kg$^{-1}$) and horses (1.2 km kg$^{-1}$). 5. Of the total intake of horses (3.25 kg DM day$^{-1}$), the Forb community alone accounted for 40%. Sheep (0.74 kg DM day$^{-1}$) resembled horses in this respect. In contrast, the contribution of this community was negligible in the diet of goats in which the Grass-F community contributed most to the intake. 6. Forbs were the largest dietary category for all animal species. The selection ratio varied from 0.7 to 11.3 for forbs, 1.0 to 7.2 for sedges and 1.1 to 2.5 for grasses. 7. Response breadth (in terms of species grazed) was similar for horses and sheep (0.46 vs. 0.43) and somewhat wider for goats (0.49). 8. Grazing pressures below the carrying capacity of the community appeared to favour botanical diversity.

Abstract: This paper reviews the investigations of Prof. L. V. Krushinsky and his colleagues into the genetics of complex behaviors in mammals. The ability of animals to extrapolate the direction of a food stimulus movement was investigated in wild and domesticated foxes (including different fur-color mutants), wild brown rats, and laboratory rats and mice. Wild animals (raised in the laboratory) were shown to be superior to their respective domesticated forms on performance of the extrapolation task, especially in their scores for the first presentation, in which no previous experience could be used. Laboratory rats and mice demonstrated a low level of extrapolation performance. This means that only a few laboratory animals were capable of solving the task, i.e., the percentage of correct solutions was equivalent to chance. The brain weight selection program resulted in two mice strains with a 20% (90-mg) difference in brain weight. Ability to solve the extrapolation task was present in low-brain weight mice in generations 7-11 but declined with further selection. Investigation of extrapolation ability in mice with different chromosomal anomalies demonstrated that animals with Robertsonian translocations Rb(8,17) 1lem and Rb(8,17) 6Sic were capable of solving this task in a statistically significant majority of cases, while mice with fusion of other chromosomes, as well as CBA normal karyotype mice, performed no better than expected by chance. Mice with two types of partial trisomies and animals homo- and heterozygous for translocations were also tested. Although mice with T6 trisomy performed no better than expected by chance, animals with trisomy for a chromosome 17 fragment solved the task successfully. Thus, a genetic component underlying the ability to solve the extrapolation task was demonstrated in three animal species. The extrapolation task in animals is considered to reveal a general capacity for elementary reasoning. The genetic basis of this capacity is very complex.

Abstract: Directed-forgetting research with animals suggests that animals show disrupted test performance only under certain conditions. Important variables are (a) whether during training, the cue to forget (F cue) signals nonreward (i.e., that the trial is over) versus reward (i.e., that reinforcement can be obtained) and (b) given that reinforcement can be obtained on F-cue trials, whether the post-F-cue response pattern is compatible with the baseline memory task. It is proposed that some findings of directed forgetting can be attributed to trained response biases, whereas others may be attributable perhaps to frustration-produced interference. It is suggested that directed forgetting in animals should be studied using procedures similar to those used to study directed forgetting in humans. This can be accomplished by presenting, within a trial, both to-be-remembered and to-be-forgotten material.

Abstract: Using horses, we investigated the control of operant behavior by a tactile stimulus (the training stimulus) and the generalization of behavior to six other similar test stimuli. In a stall, the experimenters mounted a response panel in the doorway. Located on this panel were a response lever and a grain dispenser. The experimenters secured a tactile-stimulus belt to the horse's back. The stimulus belt was constructed by mounting seven solenoids along a piece of burlap in a manner that allowed each to provide the delivery of a tactile stimulus, a repetitive light tapping, at different locations (spaced 10.0 cm apart) along the horse's back. Two preliminary steps were necessary before generalization testing: training a measurable response (lip pressing) and training on several reinforcement schedules in the presence of a training stimulus (tapping by one of the solenoids). We then gave each horse two generalization test sessions. Results indicated that the horses' behavior was effectively controlled by the training stimulus. Horses made the greatest number of responses to the training stimulus, and the tendency to respond to the other test stimuli diminished as the stimuli became farther away from the training stimulus. These findings are discussed in the context of behavioral principles and their relevance to the training of horses.