Zoo-housed mammals do not avoid giving birth on weekends.

There is evidence that zoo visitor presence can influence the behaviour and, in some cases, adrenal response of zoo animals, and can sometimes compromise animal welfare. In some laboratory studies, significantly more primate births have been reported on weekends, when fewer people are working there, compared with weekdays when staffing levels are at their highest. Here, we investigate whether there is evidence of a "weekend effect" on births in zoo animals as a result of visitor numbers. Unlike laboratories, zoos are typically busier with visitors on weekends than on weekdays, although staffing levels remain fairly consistent across days of the week. If zoo animal parturition is sensitive to human presence, then fewer births would be expected on weekends compared with weekdays. We tested this using birth data and visitor numbers on the entrance gate from zoo records across 16 species representing artiodactyls, perissodactyls, carnivores and primates at four British zoos, to see whether there is an association between mean daily birth rates and average visitor numbers. We predict that, if there is a visitor effect, daily births should be lower on weekends than weekdays and should correlate with mean daily visitor numbers. Results showed that births for all 16 species were randomly distributed through the week, and there was no significant decline in births on weekends. We conclude that the "weekend effect", if such a thing exists, does not appear to be a feature of zoo births, suggesting that elevated weekend visitor numbers are not sufficiently stressful to trigger delayed parturition.

Is wounding aggression in zoo-housed chimpanzees and ring-tailed lemurs related to zoo visitor numbers?

Chimpanzees in laboratory colonies experience more wounds on weekdays than on weekends, which has been attributed to the increased number of people present during the week; thus, the presence of more people was interpreted as stressful. If this were also true for primates in zoos, where high human presence is a regular feature, this would clearly be of concern. Here we examine wounding rates in two primate species (chimpanzees Pan troglodytes and ring-tailed lemurs Lemur catta) at three different zoos, to determine whether they correlate with mean number of visitors to the zoo. Wounding data were obtained from a zoo electronic record keeping system (ZIMS™). The pattern of wounds did not correlate with mean gate numbers for those days for either species in any group. We conclude that there is no evidence that high visitor numbers result in increased woundings in these two species when housed in zoos. Zoo Biol. 35:205-209, 2016. © 2016 Wiley Periodicals, Inc.

Can zoo records help answer behavioral research questions? The case of the left-handed lemurs (Lemur catta).

Most zoos keep comprehensive records, which potentially form a database for use in answering some research questions, such as in veterinary and population management research. They have not, however, been widely used to answer questions about animal behavior and welfare. Here we try to assess the usefulness to behavioral research of two sorts of zoo records (ARKS, the Animal Records Keeping System, and student dissertations held on file) to test the hypothesis that ring-tailed lemurs with a left limb preference experience more negative social lives. We found that, as predicted, lemurs with a left limb preference (LH) received more aggression and were involved in less grooming than nonleft-preferent lemurs (NLH), though the differences were not statistically significant. Contrary to prediction, LH lemurs had fewer reported woundings than NLH lemurs, but again the difference was not statistically significant. We found that the ARKS reports did not contain sufficient quantified and systematic behavioral data for our purposes, although otherwise they provided an excellent context for interpreting results. The student dissertations were also of limited use, primarily because of the small time frame in which they were carried out. Because of these shortcomings we were unable to distinguish whether our inability to find significant effects was due to biological (perhaps hand preference had no consequences for the lemurs) or data reasons. We suggest that closer liaison between zoo research staff, zoo record keepers and academic supervisors could help to improve the usefulness of zoo records for behavioral research.

Measuring zoo animal welfare: theory and practice.

The assessment of animal welfare relates to investigations of how animals try to cope with their environment, and how easy or how difficult it is for them to do so. The use of rigorous scientific methods to assess this has grown over the past few decades, and so our understanding of the needs of animals has improved during this time. Much of the work in the field of animal welfare has been conducted on farm animals, but it is important to consider how the methods and approaches used in assessing farm animal welfare have been, and can be, adapted and applied to the measurement of welfare in animals in other domains, such as in zoos. This is beneficial to our understanding of both the theoretical knowledge, and the practicability of methods. In this article, some of the commonly-used methods for measuring animal welfare will be discussed, as well as some practical considerations in assessing the welfare of zoo animals.