PUBLICATIONS

PEREZ, B. C., MEHRKAM, L. R., FOLTZ, A. R., & DOREY, N. R. (2018). EFFECTS OF ENRICHMENT PRESENTATION AND OTHER FACTORS ON BEHAVIORAL WELFARE OF PANTROPICAL SPOTTED DOLPHIN (STENELLA ATTENUATA). JOURNAL OF APPLIED ANIMAL WELFARE SCIENCE, 21(2), 130-140.

Environmental enrichment is a crucial element of promoting welfare for animals in captivity. However, enrichment programs are not always formally evaluated for their efficacy. Furthermore, there is little empirical evidence of enrichment evaluation for species of small cetaceans in zoological settings. A wide range of variables may potentially influence enrichment efficacy and how it in turn affects behavior. The purpose of this study was to determine the most preferred environmental enrichment, and method of presentation, for a species that has not been well studied in captivity, the pantropical spotted dolphin (Stenella attenuata). In order to determine which enrichment items and method of presentation were most effective at eliciting enrichment interaction, we systematically examined how several variables of enrichment influenced enrichment interaction. The results suggested that presenting enrichment after training sessions influenced interaction with the enrichment. The results also indicated preference for enrichment type and a specific enrichment device. Finally, factors that influenced interaction were also found to influence aberrant behavior. The results support the premise that enrichment be “redefined” for each species and each individual.

MEHRKAM, L. R., HALL, N. J., HAITZ, C., & WYNNE, C. D. (2017). THE INFLUENCE OF BREED AND ENVIRONMENTAL FACTORS ON SOCIAL AND SOLITARY PLAY IN DOGS (CANIS LUPUS FAMILIARIS). LEARNING & BEHAVIOR, 45(4), 367-377.

The domestic dog is an ideal model species in which to study the genetic and environmental factors that influence play behavior. Dogs exist in a wide variety of breeds and frequently engage in multiple forms of play. In the present study, we investigated whether the levels of solitary and social play differed between dogs of three breed types with distinct predatory motor pattern sequences (herding dogs, retrievers, and livestock guarding dogs [LGDs]). Furthermore, we investigated how environmental factors (social and nonsocial contexts) influenced play in dogs of these breed types. Groups of breed-matched dyads with working experience and of equivalent age, sex, and neuter status ratios were exposed to four experimental test conditions and two control conditions in randomized orders. With respect to solitary play, environmental context did have a significant effect, with toys reliably producing the highest levels of solitary play across all breed types. Retrievers engaged in significantly higher levels of solitary play overall than LGDs, and there was a trend in comparison to herding dogs. In contrast, neither environmental context nor breed had a significant effect on social play levels; however, neuter status of the dyads did have a significant effect on social play, with mixed-status dyads engaging in significantly higher levels of social play than same-status dyads. Our findings provide experimental evidence for identifying proximate, environmental stimuli that reliably facilitate social and solitary play and discuss possible genetic (i.e., breed type) and lifetime influences on the form of play in domestic dogs.

MEHRKAM, L. R., & WYNNE, C. D. (2014). BEHAVIORAL DIFFERENCES AMONG BREEDS OF DOMESTIC DOGS (CANIS LUPUS FAMILIARIS): CURRENT STATUS OF THE SCIENCE. APPLIED ANIMAL BEHAVIOUR SCIENCE, 155, 12-27.

In both popular media and scientific literature, it is commonly stated that breeds of dogs differ behaviorally in substantial, consistent and predictable ways. Since the mid-twentieth century, scientists have asked whether meaningful behavioral differences exist between breeds of dogs. Today, there are over 1000 identified dog breeds in the world, but to date, fewer than one-quarter of these are represented in studies investigating breed-specific behavioral differences. We review here scientific findings of breed differences in behavior from a wide range of methodologies with respect to both temperament traits and cognitive abilities to determine whether meaningful differences in behavior between breeds have been established. Although there is convincing scientific evidence for reliable differences between breeds and breed groups with respect to some behaviors (e.g., aggression, reactivity), the majority of studies that have measured breed differences in behavior have reported meaningful within-breed differences has well. These trends appear to be related to two main factors: the traits being assessed and the methodology used to assess those traits. In addition, where evidence for breed differences in behavior has been found, there is mixed consistency between empirical findings and the recognized breed standard. We discuss both the strengths and limitations of behavioral research in illuminating differences between dog breeds, highlight directions for future research, and suggest the integration of input from other disciplines to further contribute to our understanding of breed differences in behavior.

MEHRKAM, L. R., & DOREY, N. R. (2014). IS PREFERENCE A PREDICTOR OF ENRICHMENT EFFICACY IN GALAPAGOS TORTOISES (CHELONOIDIS NIGRA)?. ZOO BIOLOGY, 33(4), 275-284.

It is widely acknowledged that environmental enrichment plays an important role in promoting the welfare of captive animals. However, a topic of debate is whether an animal's preference for an enrichment strategy is any indicator of its efficacy. In addition, relatively few studies have evaluated environmental enrichment strategies for non-mammalian species. In the present study, we compared the results of an observational evaluation of enrichment efficacy with the results of a paired-stimulus preference assessment for three Galapagos tortoises. In the observational study, object enrichment (boomer balls and a free-flowing sprinkler) and keeper interactions (shell scrubbing and neck rubbing) were evaluated systematically for their effects on locomotion, species-typical behavior, aggressive and non-aggressive conspecific interactions, and enclosure. Preference assessments were subsequently conducted in which subjects could choose the enrichment strategy to be implemented. All subjects preferred keeper interactions consistently over object enrichment. Our results suggest that enrichment preference was a variable predictor of efficacy across enrichment species-typical behavior, activity levels, enclosure use, and aggressive and non-aggressive conspecific interactions strategies. Preference predicted efficacy for promoting species-typical behavior (1/3 subjects), activity levels (2/3 subjects), and enclosure use (2/3 subjects), but not conspecific interactions (0/3 subjects). The results suggest that preference may be an efficient predictor of enrichment efficacy when daily observational evaluations are not practical; however, the predictive utility of preference assessments may depend on the behavioral goal of the enrichment strategy. We discuss the need for future research examining the relationship between preference and enrichment efficacy—as well as other potential indicators of enrichment effectiveness—in captive animals.