bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.64898/2026.10.15.759480

Parental death destabilizes wolf packs despite the benefits of larger pack size

Bott, C. A.·Brown, R.·MacNulty, D. R.
View original source ↗Export metadata ↓

Abstract

1. Cooperative breeding is a fundamental feature of many animal family groups. However, few studies have quantified whether variation in group size meaningfully buffers social and reproductive consequences following parental death. 2. Using 17 years of data from a gray wolf (Canis lupus) population in Oregon, USA, we evaluated how parental death (the death of one or both parents) influenced pack dissolution, reproductive failure, and pup recruitment, and whether larger pack sizes mitigated these effects. 3. Across 303 pack-years, we recorded 69 parental deaths, 39 pack dissolutions, and 112 reproductive failures. Packs that experienced parental death were nearly five times more likely to dissolve (95% CI: 2.12-11.12), nearly 16 times more likely to fail reproductively (95% CI: 5.34-47.26), and recruited 66% fewer pups (95% CI: 49-78% fewer) than packs in which both parents survived. 4. Larger packs were associated with improved demographic outcomes overall, but these group-size benefits were insufficient to fully offset the elevated risks associated with parental death. 5. Our results show that numerous individuals can provide generalized pack-level demographic resilience but do not functionally replace parental roles, highlighting the importance of evaluating social structure in addition to population size. 6. By clarifying the limits of social buffering in a cooperatively breeding carnivore, this study advances understanding of how social systems respond to parental death.

Explore related subjects

animal behavior and cognitionPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Bott, C. A., Brown, R., MacNulty, D. R.. 2026-10-16. Parental death destabilizes wolf packs despite the benefits of larger pack size. https://doi.org/10.64898/2026.10.15.759480

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

KEEP EXPLORING

Related preprints

bioRxiv2026

Viewing geometry and pattern type shape the detectability of snakes

Protective coloration can reduce predation risk by altering how prey are detected, recognised, or attacked. High-contrast markings may function as warning signals, camouflage, or both. In snakes, dorsal colour patterns are highly variable but the function remains debated, particularly because their appearance to an observer may change with viewing distance and angle. This study tested whether the function and efficacy of common snake pattern types (blotches, spots, diamonds, zig-zags and bands) is observer-view dependent, mediated by viewing distance and angle. Artificial snake models marked with these different pattern types that are broadly common across snake taxa, were placed in woodland habitat with a mixed shrub and grass understorey in Cornwall, UK, with photographs taken for evaluating levels of predicted camouflage and contrast against the background. Next, human volunteers searched for models, and we recorded detection distances and angles. Field results showed no significant difference in overall detection rates between pattern types; however, zigzag-patterned models were more likely to be detected at significantly shorter distances than blotch-patterned models, with a marginal trend towards shorter distances than diamond-patterned models, indicating effective longer-range camouflage. Detection risk did not alter gradually as volunteers approached but increased abruptly, correlating with image analyses showing that levels of predicted disruptive camouflage decreased with reduced distance. When detection was analysed using viewing angle, an advantage of zigzag patterns was robust to geometric scale, and observer height may further shape detection through viewing geometry. These findings suggest that snake dorsal patterns could potentially serve dual roles in reducing detection from afar, while being more conspicuous at close range. In addition, the results highlight the need to consider three-dimensional viewing geometry, including distance and visual angle, when evaluating the ecological function of animal coloration.

animal behavior and cognition↗
bioRxiv2026

Camouflage functions of juvenile giant panda colouration in forest environments

The contrasting black-and-white coloration of the giant panda (Ailuropoda melanoleuca) has long attracted attention. Recent works suggest this contrasting pattern may generate camouflage-relevant visual effects. However, most previous studies have focused on adult pandas, whereas juveniles may face greater predation risk and may therefore represent a more ecologically relevant life stage for testing concealment hypotheses. We investigated whether juvenile panda coloration provides the potential for camouflage through background matching or disruptive coloration, and how this potential is shaped by vegetation cover, illumination and background position. We used life-sized juvenile panda models with natural and experimentally modified coloration by adjusting the relative proportions and spatial arrangement of white, black, and grey patches. Models were photographed in temperate woodland environments at ground level and against canopy backgrounds, under sunny and cloudy conditions, with and without vegetation occlusion. We quantified colour and luminance contrast, as well as edge-disruption metrics, using dichromatic canid and felid visual models. Natural juvenile panda coloration influences target-background contrast and edge-disruption, although these effects varies with vegetation, lighting, background height and visual model. Vegetation cover significantly reduced contrast and increased edge disruption metrics, while bright light condition only increased the metrics of edge disruption. Background position affected camouflage-relevant metrics in a context- and observer-dependent manner: under vegetation occlusion, canopy placement reduced chromatic contrast under felid-like vision, whereas ground-level placement reduced luminance contrast under both visual models. Alterations to patch extent and boundary arrangement modified camouflage-relevant metrics under specific environmental conditions, suggesting that the natural arrangement of pelage boundaries may enhance concealment under specific conditions. Overall, our findings support the hypothesis that juvenile giant panda coloration can produce visual effects consistent with potential camouflage, while highlighting the importance of habitat structure and viewing context in shaping camouflage.

animal behavior and cognition↗
bioRxiv2026

From Wandering Thoughts to Mental Stillness: A Minimal Computational Statistical-Mechanical Model of Driven Relaxation

Reduced spontaneous thought during meditation is often described phenomenologically, but a mechanistic account should specify how a dynamical system can enter and persist in such a regime. Here we formulate a minimal statistical-mechanical model in which a dimensionless coordinate, q, represents a coarse-grained propensity for spontaneous-thought activity, and a slowly relaxing variable, r of t, represents the history-dependent effect of an attentional manipulation. The model combines a tilted double-well landscape with Langevin noise, allowing a high-q and a low-q dynamical regime to coexist. We numerically integrate the model under a controlled focusing protocol followed by removal of the drive and quantify low-state occupancy, first-passage times, dwell times, occupancy entropy, and transition entropy. For the chosen dimensionless parameterization, increasing the drive amplitude produces a sharp crossover in low-state occupancy near the deterministic spinodal threshold, A-sub-sp, approximately equal to 0.0148. At a noise intensity of D equal to 0.01, the probability of occupying the low-q regime at drive removal increases from 0.094 at A equal to zero to 0.994 at A equal to 0.02, while the mean first-passage time decreases from 48.0 to 13.5 model time units. Noise produces a non-monotonic effect: for A equal to 0.01, low-state occupancy at drive removal is only 0.033 at D equal to 0.0025, rises to 0.842 at D equal to 0.02, and falls to 0.718 at D equal to 0.04. Strong driving also reduces the effective number of occupied states while changing transition entropy much less, illustrating why a single entropy measure cannot identify thoughtlessness. These results do not establish that human neural dynamics obey this model. Instead, they show that a driven stochastic bistable system can generate the qualitative sequence of focusing, switching, relaxation, and metastable low-activity residence, and they provide quantitative predictions that can be tested against time-resolved neural recordings and independent reports of subjective experience.

animal behavior and cognition↗