Regular monitoring of the behavior, habitat use, and appearance of animals can provide valuable insight into their welfare. These ongoing data can help identify meaningful trends that can be acted upon to enhance welfare, and potentially reveal individual preferences and patterns that can facilitate care tailored to the individual. To provide a low cost, flexible, user-friendly tool for staff to conduct systematic behavioral monitoring, Lincoln Park Zoo, with development support from Zier Niemann Consulting, created the ZooMonitor app. With ZooMonitor, users can record the behavior and habitat use of animals using standardized animal behavior recording methods as well as log individual characteristics such as body condition or coat/feather quality. These data can be recorded using computers or tablet devices, and data are uploaded to a cloud server where the user can conduct automated reliability tests to check observer consistency and generate built-in reports such as activity budgets and heat maps showing how animals use their available space. To demonstrate the use of ZooMonitor in an ongoing monitoring program, two case studies from Lincoln Park Zoo are presented: 1) promoting increased foraging and broader habitat use of pygmy hippos (Choeropsis liberiensis); and 2) tracking feather condition changes in a flock of domestic chickens (Gallus gallus). These examples highlight the importance of standardized monitoring and use of digital tools like ZooMonitor to enable science-based husbandry practices and promote positive welfare for animals in human care.

The way human adults grasp objects is typically influenced by their knowledge of what they intend to do with the objects. This influence is reflected in the end-state comfort effect: Actors adopt initially uncomfortable postures to accommodate later task demands. Although many experiments have demonstrated this effect, to the best of our knowledge its phylogenetic roots have not been investigated. In two experiments, we tested whether 9 cotton-top tamarin monkeys would show the end-state comfort effect. We did so by presenting the monkeys with a small cup containing a marshmallow. The cup was suspended in different orientations. The monkeys inhibited their natural grasping tendencies and adopted unusual grasping postures to accommodate subsequent task requirements, thus demonstrating the end-state comfort effect. This outcome provides evidence for more sophisticated motor planning than has previously been ascribed to this and related species.

The way human adults grasp an object is influenced by their recent history of motor actions. Previously executed grasps are often more likely to reoccur on subsequent grasps. This type of hysteresis effect has been incorporated into cognitive models of motor planning, suggesting that when planning movements, individuals tend to reuse recently used plans rather than generating new plans from scratch. To the best of our knowledge, the phylogenetic roots of this phenomenon have not been investigated. Here, the authors asked whether 6 cotton-top tamarin monkeys (Saguinus oedipus) would demonstrate a hysteresis effect on a reaching task. The authors tested the monkeys by placing marshmallow pieces within grasping distance of a hole through which the monkeys could reach. On subsequent trials, the marshmallow position changed such that it progressed in an arc in either a clockwise or counterclockwise direction. The authors asked whether the transition point in right- versus left-handed reaches would differ depending on the direction of the progression. The data supported this hysteresis prediction. The outcome provides additional support for the notion that human motor planning strategies may have a lengthy evolutionary history.

The use of enzyme immunoassays (EIA) for the non-invasive measurement of glucocorticoids provides a valuable tool for monitoring health and welfare in sensitive species. We validated methods for measuring fecal glucocorticoid metabolites (FGM) using the response to veterinary exams for four species of callitrichine monkeys: golden lion tamarin (Leontopithecus rosalia, n = 7), callimico (Callimico goeldii, n = 2), pied tamarin (Saguinus bicolor, n = 2), and white-fronted marmoset (Callithrix geoffroyi, n = 2). Routine veterinary exams were performed for the golden lion tamarins and callimicos, but exams for the pied tamarins and white-fronted marmosets were prompted by the death of a social partner. Prior to veterinary exams, fecal markers were evaluated to allow collection of individual samples and estimate approximate gut transit times. Based on this assessment, individual markers were fed in the afternoon, and fresh morning fecal samples were collected throughout this study. Following a veterinary exam, FGM increased roughly 3- to 28-fold above baseline in all species. Although FGM for most species returned to baseline concentrations within 24-48 h, the marmosets exhibited a progressive increase in FGM after an exam in response to the death of a breeding female and subsequent hand-rearing of a neonate. Individual differences were noted in the callimicos and tamarins, with higher baseline FGM levels in females vs. males, although small sample size precluded a clear determination of sex differences. To our knowledge, this is the first study to measure FGM in callimicos and white-fronted marmosets and the first to compare FGM across callitrichine species. These findings highlight the broad applicability of this EIA to measure the stress response of callitrichine monkeys. The progressive increase in FGM in the marmosets during hand-rearing of a neonate suggests that care should be taken to minimize this disturbance as much as possible.