Abstract
The effectiveness of enrichment for improving health and well-being in laboratory, agricultural, and zoo settings has been well-established, but little research has been done on the value of enrichment in facilitating successful reintroduction of rescued animals.1,2,3 Considering that the primary emphasis in rehabilitation facilities is on treating injury and disease, it is perhaps not surprising that little attention has been given to the possible value of behavioral interventions in facilitating successful reintroduction.1,2,4 However, recent studies have demonstrated the importance of enrichment as a useful tool for weight and nutritional management, reduction of stereotypical behaviors, increasing motivation, and expression of species-typical behavior.5,6,7 The objective of this study was to see if the same types of enrichment used in permanently captive settings can be effective in wildlife rehabilitation settings. Thirty-two neonatal Eastern Pacific harbor seal (Phoca vitulina richardii) pups were randomly assigned into experimental and control pools during rehabilitation at The Marine Mammal Center in Sausalito, CA. Pups in the experimental group (EP) were exposed to five types of enrichment that elicit species-typical behaviors (e.g., foraging, exploring, diving, etc.). Trials took place three times a day for 30 minutes over the course of three months. Control pups (CP) were housed in standard, unenriched pools. Variables examined included stereotypical behaviors, fecal glucocorticoid metabolites (FGM), time spent underwater, oxygen storage capacity, and number of days in rehabilitation. Thus far, data analysis indicates that pups in EP displayed significantly fewer (p=0.03) stereotypical behaviors than pups in CP and that there is a positive relationship (p=0.06) between stereotypical behaviors and the days it took for pups to independently forage. Additionally, pups in EP spent significantly more (p<.01) time interacting with foraging enrichment than with structural enrichment. These results indicate that foraging-based enrichment might improve the developmental rate of rehabilitating seal pups and reduce stereotypical behaviors. Moreover, preliminary data analyses show a trending difference in total time spent underwater between the EP and CP, therefore promoting diving behaviors that are critical for survival upon release. This study extends the literature on enrichment to rehabilitation settings, and the results support enrichment as a potential behavioral intervention to improve the welfare of rehabilitating seal pups, reduce the costs of rehabilitation, and increase the likelihood of survival of stranded seals that are reintroduced to the wild.
Acknowledgements
Special thanks to the National Wildlife Rehabilitation Association for funding, to Dr. Dan Crocker for assistance with the cortisol analysis, to Dr. Cara Field for assistance with the blood oxygen storage analysis, and to The Marine Mammal Center veterinary staff, volunteer crews, and the research assistants at TMMC and CSUSM for their cooperation and support.
* Presenting author
+ Student presenter
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