Travel Reference
In-Depth Information
we only need to know that cyanide can instantly shut down our mitochondria,
causing all the rest of our cellular metabolism to shut down as well.
The bamboos in this Madagascan forest, like many other plants around
the world, make chemical compounds that contain cyanide. These com-
pounds protect them against attacks by insects and browsing animals. The
bamboos must protect their own mitochondria from cyanide poisoning, so
they make their cyanide molecules harmless by attaching them to sugars.
The combined molecules act like time bombs. When they are eaten by insects
and animals they break down and the cyanide is released.
Some lemurs have evolved the ability to eat this deadly poison without
being harmed. All three bamboo lemurs at Ranomafana can tolerate small
amounts of cyanide in their diets, but the golden lemur takes the prize for
being the most resistant. Only the golden lemur can eat the deadly shoots of
the most cyanide-laden bamboo species. As these lemurs munch through
the tender shoots they ingest enough cyanide each day to kill a similar-sized
cyanide-sensitive animal a dozen times over.
Nobody knows how the golden lemur accomplishes this feat, but its
droppings are rich in cyanide, showing that it somehow avoids absorbing
this highly poisonous substance through its digestive tract. This ability has
enabled it to carve out an ecological niche denied even to the other two
bamboo-eating lemurs with which it shares the forest. The greater and lesser
bamboo lemurs are forced to eat woodier, less nourishing parts of the plants
because these parts have much less cyanide.
2
The food-based ecological niches occupied by these three species of
bamboo lemur are quite distinct from those of the other lemurs in the forest.
The wooly lemurs that I had taken a mud bath to photograph prefer to eat
the leaves and bark of broad-leafed trees, and the other lemur species have
their own specialties.
Cyanide is not the only reason that the bamboo lemur species preferen-
tially choose dif erent tissues to eat, but it is an important factor that helps
Figure 58
(
opposite
) A greater bamboo lemur,
Prolemur simus
, noshes on its favorite food
in Ranomafana's bamboo forest. Thought to be extinct, it has been rediscovered by Patricia
Wright, Madagascar's “lemur lady.”
