The presence of human visitors has been shown to affect the behaviour of several different mammalian species in a number of different zoos, but the behavioural changes observed are not always consistent with a simple ‘stressful influence’ explanation. Data for non-primate species are too sparse to draw meaningful conclusions; but for primates, the evidence reviewed in this paper allows several hypotheses to be tested. Neither a social facilitation nor an audience attraction hypothesis can be generally supported by the available studies. However, these studies are consistent with a general stressful influence hypothesis, although the extent of this influence is itself affected by other variables, notably species and housing differences. There is some evidence that chronic exposure to human audiences may lessen this stressful influence in some species; and in certain circumstances (notably where some members of the public throw food) the effect of the audience is almost an enriching one.

Municipal regulations and humane movement policies often restrict or discourage the use of ‘exotic’ species as companion animals. However, confusion arises because the term ‘exotic’ is used in various ways, and because classifying species as exotic or non-exotic does not satisfactorily distinguish suitable from unsuitable companion animals. Even among commonly kept species, some appear to be much more suitable than others. Instead, decisions about suitable companion animal species need to be based on a number of relevant issues. As ethical criteria, we considered that keeping a companion animal should not jeopardize - and ideally should enhance - its welfare, as well as that of its owner; and that keeping a companion animal should not incur any appreciable harm or risk of harm to the community or the environment. These criteria then served as the basis for identifying and organizing the various concerns that may arise over keeping a species for companionship. Concerns include how the animals are procured and transported, how well their needs can be met in captivity, whether the animal poses any danger to others, and whether the animal might cause environmental damage. These concerns were organized into a checklist of questions that form a basis for assigning species to five proposed categories reflecting their suitability as companion animals. This assessment framework could be used in creating policy or regulations, and to create educational and decision-making tools for pet retailers, animal adoption workers, and potential owners, to help prevent animals from being placed in unsuitable circumstances.

This study examined the effects of enriching the environment on the learning abilities of growing pigs. Eighty-four pigs were housed in either barren or enriched environments from birth to 14 weeks. The barren environments were defined as intensive housing and the enriched environments incorporated extra space, including areas which contained peat and straw in a rack. The learning abilities of pigs from both environments were tested at 15-17 weeks using an operant task which involved pigs learning to push a panel for a reward and a maze test which involved spatial learning. Pigs from enriched environments learned both the operant task and the maze task more rapidly than their counterparts from barren environments. These results suggest that the cognitive development of pigs may be impaired in intensive housing systems.

In order to be suitable, a contraceptive method should have little or no effects on social organization or behaviour. In callitrichids, changes in socio-sexual interactions between group members, due to hormonal changes induced by contraception, may have consequences for the reproductive inhibition of offspring in their natal group. This may lead to an increased rate of inbreeding. In this paper we report on the endocrinological and behavioural effects of contraception in golden-headed lion tamarins, using data obtained through a world survey and an observational study. Hormonal analysis of urinary oestrone conjugate levels in melengestrol acetate (MGA)-implanted females confirmed earlier preliminary findings (Van Elsacker et al 1994): MGA implants inhibited reproduction through the suppression of ovulation and regular ovarian cycles in the implanted female, while the occurrence of ovarian cycles in the oldest female offspring of each group was not affected. Sexual interactions between the dominant adults still occurred but underwent temporal changes. Reproductive inhibition in female offspring was maintained. Social interactions between group members altered in a non-consistent way but did not have an impact on the stability of the study groups during the study. In principle, MGA implants do not have a detrimental impact on the behaviour of group members. The suitability of MGA implants from a behavioural point of view depends on the extent to which those involved wish to preserve the entire range of natural behaviours for this species. The behavioural effects of other contraceptive methods are still largely unknown.

It has been claimed that the present farming environment does not meet foxes’ needs for social behaviour. In this study we measured the welfare of farmed blue foxes, Alopex lagopus, housed in two different social and spatial conditions: i) traditional housing (group T) where a male and a female cub were housed together and their vixen alone in standard (1.2m2) fox cages; and ii) family housing (group F) where a vixen and her five cubs were housed together in a connected six-cage system (7.2m2). Production-related welfare parameters (weight gain and the incidence of bite wounds on fur) as well as physiological ones (adrenal mass and serum Cortisol response to ACTH administration) were measured in these two groups.

No differences were found in any of the measured parameters between the vixens housed in traditional and family units. In cubs, there was less difference between the sexes in weight gain in group F than in group T, and a significantly lower weight gain was evident only in group T female cubs. The serum Cortisol level in response to an ACTH challenge was higher in group T cubs and independent of the sex of the animal, while heavier adrenals were observed in group T male cubs only. We conclude that the enlarged cage system combined with group housing had some beneficial effects on the measured performance- and welfare-related indicators in blue fox cubs.

Brushtail possums, Trichosurus vulpecula, are New Zealand's most serious vertebrate pest, facilitating the spread of bovine tuberculosis to livestock, and causing severe damage to native flora and fauna. Possum control has become a national research priority, involving the use of large numbers of captive possums. Successful adaptation of these animals to captivity is important for the welfare of the possums and for the validity of experimental results. The objective of this study was to determine, by behavioural means, the time individually caged possums required for adaptation to captivity. We used a simple behavioural measure - a possum's daily response to a caregiver at feeding (a feeding test) - to assess changes in the behaviour of possums after arrival in captivity. We also recorded changes in possum body weight throughout this period. Initially most possums ‘avoided’ the caregiver, but within 7 days more than 80 per cent of animals no longer avoided. ‘In den’ and ‘approach’ behaviour rapidly increased for the first 14 days in captivity, after which den use became less common as more possums ‘approached’ the caregiver. By day 29 of captivity, more than 80 per cent of the possums ‘approached’ the caregiver. The possums’ body weight did not change significantly during the first 14 days in captivity, but had increased significantly by day 28, and continued to increase for at least 6 weeks after capture. These data suggest that most possums adapt to captivity within 4 weeks. For the welfare of possums and the reliability of experimental results, we recommend that possums are not used in experiments until at least 4 weeks after capture.

Guidelines for the housing of dairy cows do not address the provision of supplementary lighting in passageways, other than for inspection of the animals. Two experiments were conducted to investigate whether lighting passageways to various intensities influenced the locomotion of dairy cows. The first experiment compared the locomotion of dairy cows in a dark or lighted passageway as they walked back to their accommodation from milking. When the passageway was dark, the cows took shorter but more rapid steps - which probably increased their stability. In the second experiment, cows walked down a cubicle passageway to receive a food reward, with the light intensity in the building varying from 0-250 lux. Step length and stepping rate were recorded, as well as the angles of the cows’ leg joints (which were measured from video recordings). Once again, the cows increased their stepping rate in the dark, and this resulted in an increased walking rate, perhaps because they wished to return more rapidly to other members of their group and found the darkness aversive. In addition, the arcs of travel of the metacarpophalangeal joint and of the fore- and hindfeet angles to the floor were reduced in the dark, probably increasing the cows’ stability, and were greatest at 119 lux. The slowest walking rate was observed at 39 lux. Hence, the optimum illumination for dairy cow locomotion may lie approximately between 39 and 119 lux, as measured by our technique.

We conclude that during locomotion in dark passageways cows have to modify their walking behaviour significantly, so that the provision of at least a low level of lighting is desirable at night.

Electrocution of an animal is inhumane if it is not rendered instantaneously insensible by the application of sufficient current density within vital centres of the brain. Application of electric current which does not achieve this, is likely to cause severe pain. The humane aspects of electrical lancing have aroused widespread concern and debate.

For an electrically lanced whale of the size of those currently hunted, previous research has indicated that the current densities produced in the heart and brain are unlikely to reliably render the animal insensible or stop its heart. This study supports these findings and demonstrates that the presence of salt water/immersion may further reduce current densities. Evidence for the failure of the electric lance includes the necessity for multiple and prolonged applications of electric current.

Reasons for the failure of the electric lance include non-optimal current injection sites, insufficient current injected, the presence of salt water, and the trauma caused by the explosive harpoon. The efficacy of the electric lance may be falsely exaggerated for reasons associated with blood loss and misdiagnosis of death. All evidence clearly indicates that attempts to stop the heart by electrocution will cause severe pain to an already traumatized animal.

We suggest that the use of the electric lance is clearly inhumane, and are pleased to announce that its use in Japanese whaling operations was reportedly discontinued as from 1997.