Myth, marula, and elephant: an assessment of voluntary ethanol intoxication of the African elephant (Loxodonta africana) following feeding on the fruit of the marula tree (Sclerocarya birrea)

Abstract

Africa can stir wild and fanciful notions in the casual visitor; one of these is the tale of inebriated wild elephants. The suggestion that the African elephant (Loxodonta africana) becomes intoxicated from eating the fruit of the marula tree (Sclerocarya birrea) is an attractive, established, and persistent tale. This idea now permeates the African tourist industry, historical travelogues, the popular press, and even scholastic works. Accounts of ethanol inebriation in animals under natural conditions appear mired in folklore. Elephants are attracted to alcohol, but there is no clear evidence of inebriation in the field. Extrapolating from human physiology, a 3,000-kg elephant would require the ingestion of between 10 and 27 L of 7% ethanol in a short period to overtly affect behavior, which is unlikely in the wild. Interpolating from ecological circumstances and assuming rather unrealistically that marula fruit contain 3% ethanol, an elephant feeding normally might attain an ethanol dose of 0.3 g kg(-1), about half that required. Physiological issues to resolve include alcohol dehydrogenase activity and ethanol clearance rates in elephants, as well as values for marula fruit alcohol content. These models were highly biased in favor of inebriation but even so failed to show that elephants can ordinarily become drunk. Such tales, it seems, may result from "humanizing" elephant behavior.