Can a traditional partner preference test quantify monogamous behavior in captive coyotes?

Social monogamy is a unique social system exhibited by only 3-5% of mammalian taxa; however, all wild canid species exhibit this social system. Despite the high prevalence of social monogamy among canids, little is known about how they form selective social attachment relationships among non-kin. Thus, we aimed to quantify monogamous behavior in a highly ubiquitous canid, the coyote (Canis latrans). We adapted the three-chambered partner preference test, which was originally developed for prairie voles (Microtus ochrogaster), to assess social preference in mated pairs of captive coyotes at the USDA Predator Research Facility. We quantified monogamy-related behaviors, such as time spent in spatial proximity to a pair-mate versus a stranger. Our behavioral ethogram also included visual seeking, olfactory investigations, ears down, scent marking, and affiliative behavior. Test subjects showed significantly greater affiliative behavior toward their partner than toward a stranger. However, there was extremely high variability both within and between coyote pairs across behavioral measures. These data suggest the need for larger sample sizes when working with species with high individual variability, as well as the need for species- and facility-specific modifications to this testing paradigm and/or ethogram to better adapt it from its laboratory and rodent-based origins.

Scavenging vs hunting affects behavioral traits of an opportunistic carnivore

Background

Human-induced changes to ecosystems transform the availability of resources to predators, including altering prey populations and increasing access to anthropogenic foods. Opportunistic predators are likely to respond to altered food resources by changing the proportion of food they hunt versus scavenge. These shifts in foraging behavior will affect species interactions through multiple pathways, including by changing other aspects of predator behavior such as boldness, innovation, and social structure.

Methods

To understand how foraging behavior impacts predator behavior, we conducted a controlled experiment to simulate hunting by introducing a prey model to captive coyotes (Canis latrans) and compared their behavior to coyotes that continued to scavenge over one year. We used focal observations to construct behavioral budgets, and conducted novel object, puzzle box, and conspecific tests to evaluate boldness, innovation, and response to conspecifics.

Results

We documented increased time spent resting by hunting coyotes paired with decreased time spent active. Hunting coyotes increased boldness and persistence but there were no changes in innovation. Our results illustrate how foraging behavior can impact other aspects of behavior, with potential ecological consequences to predator ecology, predator-prey dynamics, and human-wildlife conflict; however, the captive nature of our study limits specific conclusions related to wild predators. We conclude that human-induced behavioral changes could have cascading ecological implications that are not fully understood.

Parental habituation to human disturbance over time reduces fear of humans in coyote offspring

A fundamental tenet of maternal effects assumes that maternal variance over time should have discordant consequences for offspring traits across litters. Yet, seldom are parents observed across multiple reproductive bouts, with few studies considering anthropogenic disturbances as an ecological driver of maternal effects. We observed captive coyote (Canis latrans) pairs over two successive litters to determine whether among‐litter differences in behavior (i.e., risk‐taking) and hormones (i.e., cortisol and testosterone) corresponded with parental plasticity in habituation. Thus, we explicitly test the hypothesis that accumulating experiences of anthropogenic disturbance reduces parental fear across reproductive bouts, which should have disparate phenotypic consequences for first‐ and second‐litter offspring. To quantify risk‐taking behavior, we used foraging assays from 5–15 weeks of age with a human observer present as a proxy for human disturbance. At 5, 10, and 15 weeks of age, we collected shaved hair to quantify pup hormone levels. We then used a quantitative genetic approach to estimate heritability, repeatability, and between‐trait correlations. We found that parents were riskier (i.e., foraged more frequently) with their second versus first litters, supporting our prediction that parents become increasingly habituated over time. Second‐litter pups were also less risk‐averse than their first‐litter siblings. Heritability for all traits did not differ from zero (0.001–0.018); however, we found moderate support for repeatability in all observed traits (r = 0.085–0.421). Lastly, we found evidence of positive phenotypic and cohort correlations among pup traits, implying that cohort identity (i.e., common environment) contributes to the development of phenotypic syndromes in coyote pups. Our results suggest that parental habituation may be an ecological cue for offspring to reduce their fear response, thus emphasizing the role of parental plasticity in shaping their pups’ behavioral and hormonal responses toward humans.