Fig. 4.

Hair concentrations of EtG. EtG is a direct metabolite of ingested alcohol present in hair; hair EtG is correlated with chronic alcohol consumption. Species ingesting food likely containing alcohol are adult mammals from our study site that had access to fermenting nectar of the bertam palm: female pentailed treeshrews, male and female common treeshrews, female plantain squirrel, and male gray tree rat. For comparison, we collected hair samples from one adult male long-tailed macaque (Macaca fascicularis; body mass, 5 kg), and one adult large bamboo rat (Rhizomys sumatrensis; 2 kg) of unknown sex in other areas in Malaysia. We also obtained a hair sample from one wild adult male European roedeer (Capreolus capreolus; 16 kg) from Germany. Occasional alcohol consumption by these animals was possible as they may feed on rotting plant material. As alcohol-naïve negative controls, we used Norway rats of the out-bred WISTAR stock maintained on commercial food pellets (V 1536–000; ssniff Spezialdiaeten). Bars and whiskers represent means + SE. Numbers in brackets give the sample sizes. The limit of quantitation (LOQ) was 0.017 ng/mg. Concentrations above this limit indicate excessive drinking in humans (23).