An emphasis on ensuring animal welfare is growing in zoo and aquarium associations around the globe. This has led to a focus on measures of welfare outcomes for individual animals. Observations and interpretations of behavior are the most widely used outcome-based measures of animal welfare. They commonly serve as a diagnostic tool from which practitioners make animal welfare decisions and suggest treatments, yet errors in data collection and interpretation can lead to the potential for misdiagnosis. We describe the perils of incorrect welfare diagnoses and common mistakes in applying behavior-based tools. The missteps that can be made in behavioral assessment include mismatches between definitions of animal welfare and collected data, lack of alternative explanations, faulty logic, behavior interpreted out of context, murky assumptions, lack of behavior definitions, and poor justification for assigning a welfare value to a specific behavior. Misdiagnosing the welfare state of an animal has negative consequences. These include continued poor welfare states, inappropriate use of resources, lack of understanding of welfare mechanisms and the perpetuation of the previously mentioned faulty logic throughout the wider scientific community. We provide recommendations for assessing behavior-based welfare tools, and guidance for those developing tools and interpreting data.

As natural habitats around the globe disappear, humans and non-human primates become increasingly engaged in complex interactions, both peaceful and hostile. Sri Lanka's endemic western purple-faced langur Trachypithecus vetulus nestor persists in the majority of its range in complete sympatry with humans. Listed as Critically Endangered by the IUCN and one of the world's top 25 most endangered primates, their survival appears dependent on the tolerance of humans with whom they coexist. Our aims were to augment the limited information on T. v. nestor focusing on group composition and behavioural adaptations in relation to its heavily fragmented habitat. Research was carried out in Talangama Wetlands, Sri Lanka in 2007. The 5 groups varied in size from 11 to 19 individuals Monkeys regularly used fences, rooftops, power lines, and agricultural trees. Two groups of 19 and 16 individuals had home ranges of 3.06 and 2.86 ha respectively. They consumed a variety of foods including fruits, showing dietary flexibility; the fruits and leaves of Arctocarpus heterophyllus were the langurs' most frequently consumed foods. The langurs seem to be adapting to these human-modified environments. Notwithstanding, areas for concern include potentially fatal dangers when crossing between fragments, increasing human-primate conflict and intergroup conflict, and permanent genetic isolation.

The Critically Endangered blue-eyed black lemurEulemur flavifronsof north-western Madagascar is one of the most threatened primates. The majority of research and conservation efforts for the species have been restricted to the Sahamalaza Peninsula but there are unstudied and unprotected populations farther inland. The dearth of information regarding the transition betweenE. flavifronsand its parapatric sister species, the Vulnerable black lemurEulemur macaco, and the possibility of a hybrid population complicates conservation planning for both species. We surveyed 29 forest fragments across both species’ ranges to investigate the boundary between the taxa, whether hybrids persist, and the threats to lemurs in the region. We foundE. flavifronsin six fragments andE. macacoin 17. We never observedE. flavifronsandE. macacoin the same location and we found no conclusive evidence of hybrids. Three fragments in whichE. flavifronswas present were north of the Andranomalaza River, which had previously been considered the barrier between the two species. Based on these observations and a literature review, we provide updated ranges, increasing the extent of occurrence (EOO) ofE. flavifronsby 28.7% and reducing the EOO ofE. macacoby 44.5%. We also evaluate the capacity of protected areas to conserve these lemurs. We recommend additional surveys and the implementation of an education programme in this region to help conserve both species.

The study of calling patterns is a useful non-invasive method for determining population densities and the taxonomic relationships of rare or cryptic animal species. The Western purple-faced langur Trachypithecus vetulus nestor, endemic to Sri Lanka’s lowland rainforests, is severely impacted by forest fragmentation, with most remaining populations living almost completely in home gardens. Due to their shy nature, little is known about the behaviour of this subspecies; analysing the regular loud calls emitted by these langurs could allow for improvement of census techniques, clarification of their taxonomy, and an understanding of the impact of forest destruction on their behaviour. In 2007, we recorded the calling patterns of five male T. v. nestor at Talangama Wetlands. Time, duration, weather conditions, and stimulant of 253 calls were noted. Loud calls comprised three structural units: harsh barks, whoops and residuals. The average call contained 4 phrases and 3.8 residuals, was 38 seconds in length, had an average maximum frequency of 3.5 kHz, a formant frequency of 0.36 kHz, and a fundamental frequency of 0.2 kHz. Significant differences were found between individuals for the number of phrases and residuals within a call, two different phrase lengths, the formant frequency and the fundamental frequency. The earliest call occurred at 05:27 hrs, while the latest was made at 17:57 hrs. The greatest percentage of calls (73.5%) was heard in the morning (05:00-09:59 hrs), mostly stimulated by territorial battles with neighbouring troops. These results show that vocalisations can be used to distinguish individual males; as langurs are more often heard than seen, and most troops contain only a single adult male, vocalisations may be used to determine the number of troops in an area. Calls of this taxon also differed from the other subspecies, suggesting that they may be used to distinguish subspecies and their boundaries. Finally, calling behaviour differed from other subspecies. Deforestation may be a direct cause of different calling patterns. These baseline data form a valuable starting point for further studies of this Critically Endangered primate.

Interest in the impact of human presence on the behavior and well-being of zoo and aquarium animals is increasing. Previous work has conceptualized the presence of zoo visitors as having one of three impacts on the behavior of animals in zoos: positive, negative, or neutral. Research suggests the same species may exhibit all three responses under different conditions, calling into question whether the positive/negative/neutral framework is the most useful way of considering visitor impact on animal behavior. Here we present a model of visitor effects that unifies these three predictions. Our model suggests that zoo-goers may provide a "dither effect" for some animals living in zoos. We posit animals may show nonlinear behavioral responses over a range of visitor densities, effectively exhibiting changes in both comfortable and anxiety-like behaviors under different levels of human presence. We tested this model during two COVID-19 related closures at the San Francisco Zoo, studying seven species for evidence of nonlinear relationships between visitor numbers and animal behavior. Our results support the dither effect acting in several species observed.

Animal-based measures reflecting the welfare state of individuals are critical for ensuring the well-being of animals under human care. Anticipatory behavior is one potential animal-based measure that has gained traction in recent years, as it is theorized to relate to animals' reward sensitivity. It is of particular interest as an assessment for animals living under human care, as the predictability of the captive environment lends itself to the development of this class of behaviors. Animals are likely to exhibit anticipation in locations related to the anticipated event, often in temporally predictable time frames, and before specific contexts they experience in their day-to-day management. In this sense and under certain circumstances, anticipatory behaviors are likely to drive observed behavioral or space use patterns of animals under human care. Drawing conclusions from such data without identifying anticipation may result in misleading conclusions. Here we discuss how space, time, and context are related to patterns of anticipatory behaviors in animals under human care, how unidentified anticipation may alter conclusions regarding animal behavior or welfare under certain circumstances.