Ingestion of fat tissue from wolf prey species and its infl uence on fatty-acid composition in sled dogs

We conducted feeding experiments on Canadian Inuit sled dogs (Canis familiaris borealis) as a surrogate for wolves (Canis lupus) to examine whether fatty-acid signatures could be used to estimate relative intake of common prey in the Great Lakes area, USA. We obtained fat tissue from white-tailed deer (Odocoileus virginianus), moose (Alces alces), beaver (Castor canadensis), and domestic cow (Bos spp.), and provided 8 treatments of prescribed proportions to 6-7 dogs/treatment (total 50 dogs) over a period of 60 days. Pre and post-treatment fat-tissue samples from dogs were collected by biopsy to examine fatty-acid composition. Approximately 10 60-mg samples of fat from each prey species were analyzed using gas chromatography to develop a database of fatty-acid signatures for each prey species. Fatty-acid signatures of these 4 prey species were distinct. Fatty-acid signatures of sled dogs changed with diet consistent with prescribed treatments. However, we could not reliably reconstruct their actual diet using Iverson et al.'s (2004) model. This study demonstrates that analysis of both prey and predator's fatty-acid composition may be an innovative method to estimate dietary history of a terrestrial predator, such as wolves, but additional work is needed to make dietary predictions.