Indri

Father of the Forest

There are more than 110 different species of lemur alive on Madagascar today and they encompass a wide variety of shapes, sizes, and behaviours. At one extreme is the tiny Madame Berthe’s mouse lemur. At a mere 92 mm in length and weighing just 31 grams, it is not only the smallest lemur in the world (it can sit, quite comfortably, in an egg cup) but it’s also the smallest primate: it is 6,500 times smaller than the eastern gorilla, which, barring a few exceptionally obese humans, is considered the largest primate.

Like other mouse lemurs, Madame Berthe’s mouse lemur is nocturnal, and although at first glance it looks more like a tree-dwelling rodent, its forward-facing eyes, nails (rather than claws), and grasping hands tell the observer that it is, in fact, a (very small) primate. Confined to one small area of rainforest along the west coast of Madagascar, it feeds on fruits and the sugary secretions of insects.

At the opposite end of the scale from Madame Berthe’s mouse lemur is the 9 kg indri. This is the largest lemur alive today [1]. Unlike the ring-tailed lemur, which is a very terrestrial species, the indri hardly ever comes down to the ground. To get around in the trees, it doesn’t swing from its arms like an ape or run along the branches like a monkey. Instead, it travels through the forest using huge jumps. Launching itself from the trunk of a tree by explosively straightening its long, powerful hind legs, it travels through the air, torso upright, in a soaring bound, twisting around in mid-air to land on another trunk a few metres away. It then repeats this process again and again so that it seems to pogo from tree to tree, bouncing through the forest.

With a short, naked muzzle, large ears, and a strange facial expression that makes it look eternally spooked, the indri almost resembles a gangly, black-and-white teddy bear. But the noises that this lemur produces are far from cute. Each small family group holds its own patch of land and during the evening and early morning, their haunting, ear-splitting cries and wails echo through the forest in a great unearthly chorus as they proclaim ownership of their territory.

The first western scientist to describe the indri was the French naturalist, Pierre Sonnerat, in the late 18th century. According to an oft-repeated story, he was travelling through the Madagascan forest when his Malagasy guides spotted a large, virtually tailless type of lemur that he, Pierre, didn’t recognise. The guides supposedly shouted ‘Indry,’ which means ‘look, there [it is]’, and Pierre, taking that to be the animal’s name, included it in his description of the animal. But, as appealing as this tale is, there is no evidence that it is actually true, and ‘indri’ most likely simply comes from a local name of the animal, endrina.

Unfortunately (and this, you may notice as Madagascar Month continues, is a recurring element when it comes to Madagascan wildlife), the indri is in trouble. Classified as Critically Endangered, its exact population is unknown, although it’s thought to be somewhere between 1,000 and 10,000 individuals. Indri meat and fur are both prized by local people, and although hunting is common, habitat loss is this species’ main threat today; it is now restricted to ever-decreasing pockets of rainforest along Madagascar’s east coast. Even worse, whereas some types of lemurs, such as the ring-tailed, have healthy zoo populations that can be used for future reintroductions, indris have never been successfully kept or bred in captivity. This is partly because they live exclusively on a diet of young, fresh leaves, and eat certain foods at certain times of day, which is a very specialist diet that is difficult to replicate in a zoo.

In our next Madagascar Month post, we’ll be looking at another Madagascan mammal a strange, slinky predator called the fossa.

[1] Some of the lemurs that lived in the past were much larger than the indri. Since humans first arrived on Madagascar around 2,000 years ago, at least 17 species of lemur have gone extinct, including a sloth lemur called Archaeoindris fontoynontii that was comparable in size to a male gorilla.