bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.64898/2025.12.28.696733

Activity Budgets and Boldness as Potential Predictors of Release Readiness in Rehabilitating Javan Slow Lorises

Langgeng, A.·Sigaud, M.·Prameswari, W.·Priambada, N. P.·Rianti, P.·Moore, R.·Matsuda, I.·MacIntosh, A.
View original source ↗Export metadata ↓

Abstract

Rehabilitation centers are central to the conservation of Javan slow lorises (Nycticebus javanicus) by providing care for individuals confiscated from trade and preparing them for potential release. To evaluate behavioral readiness for reintroduction, we quantified activity budgets and boldness in 10 adult N. javanicus (7 females and 3 males) housed at a rehabilitation facility in West Java, Indonesia, from May to September 2024. Locomotion dominated activity budgets (57.14% {+/-} 24.86%), followed by resting (23.51% {+/-} 16.61%), with low rates of stereotypy (4.36% {+/-} 13.48%) and grooming (2.33% {+/-} 5.28%). Boldness tests using six novel object types revealed strong stimulus dependence: predator models suppressed approach, while enrichment and neutral objects encouraged exploration. Sex, housing conditions, and rehabilitation duration did not predict boldness, indicating inter-individual differences in responses to novelty. Principal component analysis identified an integrated bold-exploratory activity axis, suggesting that activity budgets and boldness covary as part of a behavioral syndrome rather than independent traits. Together, these results indicate that combined activity and personality metrics provide complementary indicators of behavioral welfare and release readiness, with potential to improve pre-release assessment and site matching for this critically endangered primate.

Source connections

Explore related subjects

animal behavior and cognitionPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Langgeng, A., Sigaud, M., Prameswari, W., Priambada, N. P., Rianti, P., Moore, R., Matsuda, I., MacIntosh, A.. 2025-12-29. Activity Budgets and Boldness as Potential Predictors of Release Readiness in Rehabilitating Javan Slow Lorises. https://doi.org/10.64898/2025.12.28.696733

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Automated pup-level analysis reveals distinct effects of prenatal CBD and THC exposure on maternal retrieval

This study examined how prenatal CBD and {Delta}9-tetrahydrocannabinol (THC) exposure affects maternal caregiving in C57BL/6J mice. We developed the Machine-Automated Scoring of the Pup Retrieval Test (MAS-PRT) to overcome limitations of manual behavioral scoring. MAS-PRT integrates Multi-Animal DeepLabCut for dam and pup tracking with Detectron2 for dynamic nest reconstruction. Validated against 170 manually annotated retrieval trials, the pipeline showed high concordance with manual measurements and enabled reproducible extraction of encounter latency, retrieval latency, and locomotor trajectories. Prenatal exposure did not impair general nest-building or overall home-cage maternal care. However, pups from both CBD and THC groups showed reduced body weight at postnatal day 5. Cox proportional hazards modeling revealed divergent effects by compound: CBD-exposed dams exhibited a weight-dependent increase in probability of encountering and retrieving lighter pups, independent of pup sex. Spatial tracking further showed that dams traversed significantly shorter total trajectories when retrieving female progeny exposed to either compound. Longitudinal trial-by-trial analysis indicated intact task acquisition in controls and CBD dams, whereas THC dams displayed a flattened learning curve driven by lower retrieval latencies on initial trials. Together, these findings indicate that prenatal cannabinoid exposure does not produce generalized disruption of maternal care but instead induces compound-specific alterations in maternal reactivity, retrieval kinematics, and learning dynamics.

animal behavior and cognition↗
bioRxiv2026

A comparison of female competitive traits: Female aggression peaks at nest building but female song spans multiple contexts in a temperate songbird

Female-female competition is increasingly recognized as a key driver of female ornamentation, including birdsong, which often functions in intrasexual competition. However, the specific resources females use elaborate traits to compete for remain unclear. In addition, few studies have simultaneously investigated the use of multiple competitive traits in females, despite growing independent interest in these traits (e.g., female song and aggression). We investigated the competitive contexts of female song, aggression and calling behavior in northern house wrens (Troglodytes aedon) to determine which resources females compete for across the breeding season. We simulated conspecific territorial intrusions using female song at three breeding stages representing different contexts: arrival (mate and territory acquisition), nest building (nest site and breeding status defense), and egg laying (brood defense). We tested whether female song and physical aggression varied as reproductive resources shifted across the breeding cycle. Females were significantly more aggressive during nest building, showing 5.8 times greater odds of a higher-intensity aggressive response during nest building compared to arrival. Female song output was similar across early stages but declined during egg laying, though this was not statistically significant after correction for multiple comparisons and individuals varied substantially in overall singing propensity. Non-song vocalizations varied by call type and breeding stage. Calls associated with aggression occurred most frequently during nest building, consistent with peak physical aggression responses. Together, these results identify nest building as the stage of highest female aggression, consistent with heightened competition over nest cavities and associated breeding status in this cavity-nesting species. In contrast, female song occurred across all stages and appears to function in multiple competitive contexts. This study provides evidence for context and mode-specific female signaling in a temperate songbird and highlights that females strategically use aggression, calls, and song to mediate social conflict across breeding contexts.

animal behavior and cognition↗
bioRxiv2026

Tracking human foragers and their prey reveals adaptive predator-prey dynamics

Hunting for mobile prey is thought to have played a key role in hominin evolution, by providing high-quality nutrition that supported the development of the exceptionally large human brain. However, human-prey dynamics remain poorly understood because studies have not yet tracked human foragers and their prey simultaneously. Here, we employ high resolution tracking of groups of human foragers (ice-fishers) and their prey (fish shoals) to study human-prey dynamics. Our results show that foragers adaptively combined personal and social information in deciding where to forage and for how long, closely matching the prey distribution. Prey responded dynamically to human exploitation, showing increased attraction to fishing activity, alongside decreased biting probability. Furthermore, we found that foragers adaptively relied on memory, preferentially returning to areas with high prey presence, particularly when their current return rate was low. Our results show how human foragers overcome the challenges of extracting invisible, mobile and reactive prey by tightly tuning patch-selection, patch-leaving and patch-return decisions to the distribution and behaviour of their prey.

animal behavior and cognition↗