Call of the wild: The indri call sounds like a cross between a an eerie whale song and an ambulance siren, and can be heard for a couple of miles. A group’s “song” is answered by neighboring groups; apparently this singing works better than fighting over territory. Perhaps we humans should try it; can you imagine singing contests instead of wars?

Family life: Indri don’t reach sexual maturity until they’re 7 to 9 years old, and females are probably only capable of giving birth to a single offspring every 2-3 years. Group size is 2 to 6 individuals: an adult pair with their dependent offspring. The female is dominant, and gets first chance at food. Families defend their territories with the indris’ “characteristic eerie wailing song.”

(This photo is from my trip to Madagascar in 2000.)

Conservation status: Endangered
Group size: 2-7

(This photo is from my trip to Madagascar in 2000.)

Simus live in groups of 7 to 11 individuals (sometimes as many as 25), and tend to be active around dawn and dusk. Once widespread throughout the rainforests in Madagascar, simus was “lost” to science for years, then rediscovered in living in two tiny, isolated populations in the southeastern rainforest.This species is not female dominant.

Photo op: We were lucky enough to have a group come crashing into our campsite one afternoon, settling in to eat the bamboo there for several hours. This group is habituated to humans, and came right down to eye-level to watch us — without much interest — as we watched them — with great interest.

Food and range: Simus feed almost exclusively on bamboo, chewing into live stalks and stripping the outer layers to get to the pith. The other 2 kinds of bamboo lemurs (Hapalemur aureus and griseus) eat other parts of the bamboo plant, so do not, technically, compete with Hapalemur simus for food.

As you can imagine, a group of greater bamboo lemurs can quickly do a great deal of damage to a bamboo forest. They need a large range in order to have enough bamboo to eat. In fact, the range for a small group can be 100-150 ha. (Compare that to rubriventer, with a range of 10-20 herctares.)

Conservation status: High Priority Endangered
Range: 150 hectares

(These photos are from my trip to Madagascar in 2000.)

They’re Cyanide-Proof: Golden bamboo lemurs feed almost exclusively on giant bamboo, preferring the tender new shoots and leaves, which are not eaten by any other lemur. New bamboo shoots contain high levels of cyanide — easily enough to kill an animal this size, but somehow the golden bamboo lemur is able to live on this diet. Talk about a niche — no one is challenging this animal over dinner!

Conservation status: Critically Endangered
Range: 15-80 hectares

(These photos are from my trip to Madagascar in 2000.)

Feast or famine: When primary rainforest is replaced by (introduced) dense single-species Chinese guava forests — as in much of the Ranomafana forest — red bellied lemurs get lots of guava fruit to eat … but for only a few months each year when the guavas are fruiting. Then what? They need larger home ranges to provide more fruit, or they get very, very hungry. If food is in short supply, a rubriventer family may need to travel as much as 1 km/day. Travel is instigated and led by the dominant female.

Naps: Rubriventer normally take a big nap at midday — maybe 4 hours long. This made them popular with us trackers, because we had time for lunch and a nice rest! Vine tangles make great daytime sleeping sights, and help avoid detection by lemurs’ diurnal predators, the raptors. But guess what: fewer old-growth trees means fewer vines that are big enough for sleeping sites, which means larger territories are needed.

Stink fights: Red bellied lemurs are very territorial, and do not share space with other red bellied lemur groups, although they do tolerate other species. The pair spend time scent marking boundaries, and will fight if they encounter another rubriventer group at territory borders. Sometimes this is a “stink fight,” in which they just fiercely mark territory boundaries; other times it leads to physical aggression. Rubriventer are cathemeral, or active both day and night, which may represent a transition from a nocturnal niche to a diurnal one.

Conservation status: Endangered
Range: 10-20 hectares per family

(These photos are from my trip to Madagascar in 2000.)

This photo shows the lemur sitting on a clump of figs that sprout, oddly, from the trunk of the fig tree. In this area, figs were plentiful, and served as a major source of food for the lemurs.

Fulvus are not sexually monogamous; females are observed to mate with every male in the group during their brief estrus period. Females prefer “novel” (young) males — don’t we all? After a few years, older males become socially and sexually peripheralized, providing only about 5% of the matings. No wonder the males do not provide any infant care!

(This photo is from my trip to Madagascar in 2000.)