Indigenous to the south-eastern Madagascar rainforests, the golden bamboo lemur is a plump, cat-sized primate with reddish gold fur most recently discovered by Western science. The most confounding thing about the golden bamboo lemur, however, is its diet.
In a 1986 search expedition for the greater bamboo lemur, mistakenly believed to be extinct at the time, the team discovered another lemur with golden-red colouration. Because of the colour of its fur, it was christened the golden bamboo lemur. Of the three sympatric bamboo-lemur species that coexist in the Madagascar’s forests, the golden-bamboo lemur was found to be mainly subsisting on new, young shoots of giant bamboo — a plant known to contain astonishingly high levels of cyanide toxins. Each individual lemur guzzles about 500 g of bamboo per day, thus consuming about 12 times the lethal dose of cyanide for other primates with the same body mass. The daily intake of this much cyanide is enough to kill three adult men.
A study which sought to establish the patterns of cyanide consumption in bamboo lemurs (Hapalemur), found their diets predominantly dependent on bamboo. However, there was (is?) a species-wide variation in the specific bamboo parts consumed. The golden bamboo lemur eats the highly-toxic leaf bases, shoots, and new pith, while the greater bamboo lemur eats the exponentially less-toxic mature pith of the same bamboo. The gentle or lesser bamboo lemur, on the other hand, eats the shoots of entirely another bamboo species because it cannot handle the high toxicity of its cousin’s diet. This distribution would also explain how the three species avoid competition while sharing the same habitat and food source.
An analysis of the golden lemurs’ fecal samples confirmed the presence of cyanide, suggesting that the lemurs somehow process and detoxify the lethal levels of cyanide in their diets without getting poisoned. (Interestingly, these cyanide-laden faeces are specifically chosen as food by a species of dung beetle which appears to have co-evolved with the golden lemur).
Unfortunately, the physiological process that makes the golden lemur immune to dietary toxins is as yet unknown. Scientists are running out of time as the species — one of the rarest in the world — is critically endangered because of the enduring depletion of its forest habitat due to slash-and-burn agriculture.