Cyanide Loving Lemurs
Cyanide Loving Lemurs: It sounds like a question you would hear at a pub quiz. Which species of animal ingests enough cyanide each day to kill an animal of similar size many times over? The answer is the Bamboo lemur which lives in the primary rainforest of Ranomafana national park and further south in Andringitra. Both these parks can be found in the southern part of Madagascar within a days drive of the capital Antananarivo. When I visited the park in January 2019 I was lucky enough to actually see two species of Bamboo lemur, the Golden and the Greater both of whom ingest large amounts of cyanide in their diet.
The Golden Bamboo cyanide loving lemurs were discovered by Patricia Wright in the forests around Ranomafana village in 1986 and the park subsequently opened in 1991 as a means of protecting them. Today it is one of the most popular and accessible national parks in the country and remains a centre for conservational study. During the time her team were working in Ranomafana they also found the Greater Bamboo lemur, which had not been seen at that stage since the late 1970s and was possibly thought to be extinct.
Golden Bamboo adults weigh about 1.5 kilograms and can be up to 45 centimetres in length and are listed as critically endangered with less than 1000 left in the wild. They have mostly brown but sometimes reddish fur and brown eyes with tails nearly as long at their bodies. Greater Bamboo lemurs are slightly larger at about 1.7 kilograms with grey brown fur and are even in a more precarious position with less than 150 remaining in the wild.
When Patricia Wright’s team conducted research in and around Ranomafana in the late 1980s they observed Golden Bamboo lemurs only ate one species of bamboo, eating shoots, leaves, pith and the viny part of the plant. They are fascinating animals from the point of view of evolution because the amount of cyanide they ingest from their diet is enough to kill an animal of similar size many times over but these cyanide loving lemurs are unaffected by it.
Hery, my guide for the day in Ranomafana, explained some interesting points about the behaviour of this lemur which may help to explain how the cyanide seems to have little effect. After eating they often come down from the trees and eat red soil which is abundant in Ranomafana. This red soil contains large amounts of iron and may play a role in the detoxification process. The lemurs also drink a lot of water after eating and in the height of the dry season they can be seen to be lethargic when water is limited. It is known that the cyanide is metabolised quickly and the animals which prey on them, such as the Fossa, show no signs of cyanide poisoning which means when it eats one of these lemurs, cyanide is not present in the body. It is also not present in the milk it feeds to the young either. They really are specialists of their environment which makes them all the more fascinating.
I visited Ranomafana on a misty day when the cloud cover and light rain gave the place the feel of an entirely different country than I had seen in the dry south. We hiked a forest thick with giant bamboo which was sometimes difficult to walk through and the first hour was spent looking for Golden Bamboo lemurs high up in the forest but with no luck. Because they prove difficult to find but we had a lemur spotter along with us who is familiar with their habits and locations and he went off into the forest to search for them as we looked in another areas. Eventually we got a signal from the spotter which prompted the guide, Hery, to take off in that direction with me struggling to keep up. Three Golden Bamboo lemurs were feeding on leaves up in the branches and moved off into the distance when they have had their fill. While we don’t get too close I could see their dark brown fur and brown eyes as they had their morning feed. They feed in the morning usually starting about 5.30am and continue for about 30 minutes followed by a rest period of 30-40 minutes. This continues until about 10am when they have a longer rest until about 3pm when they continue feeding and resting until dark1. This was the only sight we got of the golden bamboo lemurs but to even see these wonderful Madagascar rainforest animals felt like a stroke of luck.