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Species Profile

Indri

Indri indri

The singing giant of Madagascar's trees
Mariusba / Creative Commons

Indri Distribution

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Endemic Species
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Found in 1 country

Indri holding baby

At a Glance

Wild Species
Also Known As Babakoto, Baba-koto
Diet Folivore
Activity Diurnal+
Lifespan 16.5 years
Weight 9.5 lbs
Did You Know?

Largest living lemur: adults typically 6-9.5 kg with a 64-72 cm head-body length; tail is vestigial (~4-5 cm).

Scientific Classification

The indri (Indri indri) is the largest living lemur, an arboreal primate endemic to the rainforests of eastern Madagascar, known for its loud, far-carrying songs and vertical clinging/leaping locomotion.

Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Primates
Family
Indriidae
Genus
Indri
Species
indri

Distinguishing Features

  • Largest extant lemur; robust black-and-white coat pattern (variable by region)
  • Very short tail (appears nearly tailless)
  • Powerful hind limbs for vertical leaping
  • Loud, haunting group calls used for territorial advertisement and cohesion

Physical Measurements

Length
2 ft 5 in (2 ft 2 in – 2 ft 7 in)
Weight
17 lbs (13 lbs – 21 lbs)
Tail Length
2 in (1 in – 2 in)
Top Speed
21 mph
About 33 km/h

Appearance

Primary Colors
Secondary Colors
Skin Type Dense, woolly fur over body; largely bare, darkly pigmented facial skin; naked skin on palms/soles and nose leather. (As typical for Indriidae lemurs adapted for arboreal vertical clinging/leaping.)
Distinctive Features
  • The indri (Indri indri) is the largest living lemur. Adults weigh about 6–9.5 kg, have head-body lengths of 64–72 cm, and have almost no tail (vestigial).
  • Powerful vertical clinging-and-leaping morphology: very long hind limbs relative to forelimbs, upright posture on trunks; capable of long leaps between vertical supports (field reports commonly cite leaps on the order of ~8-10 m).
  • Round head with short muzzle; prominent, forward-facing eyes; small external ears often partly hidden by fur.
  • Toothcomb (strepsirrhine trait) and grooming claw (typically on the second toe), used for grooming and feeding on leaves/soft plant parts.
  • Arboreal, diurnal rainforest specialist endemic to eastern Madagascar; locomotion and foot/hand pads adapted to gripping bark and landing on vertical trunks.
  • Species-typical loud, far-carrying territorial/group songs (often given by pair/family groups), a key identification feature distinguishing Indri from sifakas (Propithecus) despite shared Indriidae family membership.
  • Social structure typically small cohesive groups (often a monogamous pair with offspring; group sizes commonly reported ~2-6), with strong territoriality expressed via vocal displays and scent marking.
  • Conservation: listed as Critically Endangered (IUCN); major threats include habitat loss/fragmentation (slash-and-burn agriculture, logging) and hunting, which directly reduces group persistence in remaining forest blocks.

Did You Know?

Largest living lemur: adults typically 6-9.5 kg with a 64-72 cm head-body length; tail is vestigial (~4-5 cm).

Indri songs can carry roughly up to ~2 km through rainforest and are often performed as coordinated group "choruses."

They move by vertical clinging and leaping-launching from one trunk to another and landing upright, like living springboards.

Reproduction is slow: usually a single infant after ~120-150 days gestation, with interbirth intervals commonly ~2-3 years.

Groups are small (often 2-6 individuals) and maintain territories using song and scent-marking.

Unlike many lemurs, indri are strongly diurnal and spend most of their lives high in the canopy, rarely descending to the ground.

They are Critically Endangered (IUCN Red List) due to habitat loss/fragmentation and hunting pressure, despite cultural taboos protecting them in some regions.

Unique Adaptations

  • Powerful hind limbs and elongated tarsal bones suited to explosive trunk-to-trunk leaping-shared with close Indriidae relatives like sifakas (Propithecus) and woolly lemurs (Avahi).
  • Reduced/vestigial tail: unlike many lemurs, indri rely on upright posture and precise landings rather than tail balancing in long horizontal runs.
  • Complex vocal anatomy/behavior for long-range song: structured choruses that can transmit through dense rainforest better than short calls.
  • Specialized leaf-eating physiology typical of indriids: an enlarged gut (hindgut fermentation) helps extract nutrients from fibrous leaves.
  • Strong, grasping hands/feet and nail-like grooming claw (typical lemur trait) support arboreal life, grooming, and secure vertical clinging.

Interesting Behaviors

  • Territorial chorusing: family groups give loud, patterned songs (often starting with roars) that advertise occupancy and help coordinate spacing with neighboring groups.
  • Pair and family cohesion: songs and close resting/sunbathing bouts reinforce bonds within small, stable groups.
  • Vertical clinging & leaping locomotion: they cling upright to trunks and make powerful leaps between vertical supports, then absorb impact with hind limbs while staying upright.
  • Selective folivory: they feed heavily on young leaves, plus flowers and fruit when available; feeding paths can shift with seasonal plant phenology.
  • Scent communication: glandular rubbing and urine-marking are used alongside vocal signals to maintain territories and social information.
  • Slow life history: extended infant dependency, long juvenile period, and relatively late maturity (commonly cited around ~7-9 years) make populations slow to rebound after losses.

Cultural Significance

In Madagascar, the indri (Indri indri) is called an "ancestor" by many. Local taboos often stop people from harming them, though this varies. Where taboos weaken, hunting and forest loss have caused big declines. Their loud song marks eastern rainforests and helps conservation and ecotourism.

Myths & Legends

A Madagascar tale says human family became separated in the forest; one turned into an indri (Indri indri). Its local name means "father/ancestor of Koto," showing family ties and why indri should not be harmed.

Kinship taboo legends: In many local tales, the indri (Indri indri) are seen as relatives or ancestors; harming one brings bad luck. They are 'people of the forest' who guard or punish families.

In parts of eastern Madagascar, folklore says the indri (Indri indri) sings a loud, wailing, sad song. People think it mourns a lost child (often Koto) or calls to human relatives lost in the forest.

Conservation Status

CR Critically Endangered

Facing an extremely high risk of extinction in the wild.

Population Decreasing

Protected Under

  • CITES Appendix I (all lemurs are listed; international commercial trade prohibited)
  • Madagascar national wildlife protection (lemurs are legally protected; hunting prohibited/regulated under national legislation)
  • Occurs in protected areas within its range (e.g., Andasibe-Mantadia National Park and associated reserves; additional eastern protected areas depending on subrange), though enforcement effectiveness varies

Life Cycle

Birth 1 infant
Lifespan 17 years

Lifespan

In the Wild
15–18 years

Reproduction

Mating System Monogamy
Social Structure Socially Monogamous
Breeding Pattern Long Term
Fertilization Internal Fertilization
Birth Type Internal_fertilization

Indri (Indri indri) are socially monogamous, pair-living, territorial lemurs with long-term pair bonds and loud duet songs. They breed seasonally (mating Dec–Jan, birth May–Jun after 4–5 month pregnancy), usually one infant and 2–3 year gaps. Mothers mainly care; males help guard.

Behavior & Ecology

Social Family group Group: 4
Activity Diurnal, Matutinal, Vespertine
Diet Folivore Young, tender leaves (new growth).

Temperament

Strongly territorial at the group level; intergroup interactions are typically characterized by avoidance, calling, and boundary defense rather than tolerance (Pollock 1979)
Socially cohesive and affiliative within the family group; frequent close-spacing and coordinated travel/foraging are reported (Powzyk & Mowry 2003)
Female dominance reported (consistent with many lemurs), influencing priority of access and social interactions within groups (Powzyk & Mowry 2003; general lemur patterns discussed in Kappeler 1993)
Slow life history with high parental investment: usually single offspring; prolonged juvenile dependence supports stable family-group living (Pollock 1977, 1979)
Risk-averse/cryptic during disturbance: reliance on canopy cover and rapid vertical clinging/leaping escape, with vigilance/alarm calling during perceived threats (field observations summarized in Pollock 1977)

Communication

loud, far-carrying territorial song produced as group choruses/duets; used in spacing, territorial advertisement, and pair/family cohesion; reported to carry on the order of kilometers under forest conditions E.g., ~1-2+ km) and commonly delivered in morning/late afternoon peaks (Pollock 1979; Giacoma et al. 2010; Bonadonna et al. 2014
alarm calls Short, abrupt calls) associated with aerial/terrestrial threats and triggering group vigilance/mobbing/retreat responses (Pollock 1977
contact calls during movement/coordination in dense forest canopy Powzyk & Mowry 2003
infant distress calls that elicit maternal/parental approach and carrying/comforting Pollock 1977
visual signaling: posture/orientation during calls, branch shaking, and conspicuous positioning during intergroup encounters to amplify signal salience Field descriptions in Pollock 1977, 1979
tactile communication: social grooming and close body contact supporting pair/family cohesion Powzyk & Mowry 2003
scent/chemical communication appears less emphasized than in many other lemurs, but urine/anogenital marking and sniffing investigations are reported and likely contribute to territorial and reproductive information transfer Lemur olfactory behavior overview in Kappeler 1998; indri-specific field notes in Pollock 1977

Habitat

Biomes:
Tropical Rainforest
Terrain:
Island Hilly Mountainous Valley Riverine
Elevation: Up to 5905 ft 6 in

Ecological Role

Arboreal primary consumer (folivore) and occasional frugivore in eastern Madagascar rainforests; influences canopy plant dynamics through selective browsing and contributes to plant reproduction when dispersing seeds from consumed fruits.

canopy pruning and shaping of plant growth via selective leaf browsing seed dispersal for some fleshy-fruited plants (when fruits are eaten) nutrient cycling through fecal deposition in the forest canopy/understory supporting forest food webs as prey for native predators (indirect ecosystem function)

Diet Details

Other Foods:
Young leaves Mature leaves Leaf buds and shoots Flowers Fruit Seeds Bark +1

Human Interaction

Domestication Status

Wild

Indri (Indri indri) is a wild, not domesticated lemur from eastern Madagascar rainforests. It does not have a history of domestication and survives poorly in captivity. It lives in small family groups, makes loud songs, and is threatened mainly by deforestation, habitat fragmentation, hunting, and illegal capture despite local cultural taboos protecting it.

Danger Level

Low
  • Physical injury is generally limited to defensive bites/scratches if approached, handled, or cornered (risk elevated during capture/illegal trade attempts).
  • Zoonotic disease risk typical of nonhuman primates (e.g., enteric pathogens, parasites) with close contact; risk increases with handling, captivity, or bushmeat exposure.
  • Indirect risk during fieldwork/tourism: falls/accidents in rugged rainforest terrain while tracking animals; not caused by aggression but associated with human pursuit of sightings.

As a Pet

Not Suitable as Pet

Legality: Not suitable and usually illegal: Indri indri is protected by Madagascar law and banned from selling under CITES Appendix I. Most countries ban private ownership; permits are rare and care in captivity is poor.

Care Level: Expert Only

Purchase Cost:
Lifetime Cost: $50,000 - $250,000

Economic Value

Uses:
Ecotourism Scientific research Cultural/spiritual value Ecosystem services (seed dispersal/forest ecology)
Products:
  • Non-consumptive wildlife tourism (guided forest visits, wildlife watching, photography) centered on indri songs and sightings
  • Research value (behavioral ecology, bioacoustics, conservation biology); no legitimate commercial animal products
  • Negative/illegal interactions in some contexts (habitat conversion; occasional hunting pressure in some areas despite taboos and legal protection)

Relationships

Predators 5

Fossa Cryptoprocta ferox
Madagascar harrier-hawk Polyboroides radiatus
Henst's goshawk Accipiter henstii
Madagascar ground boa
Madagascar ground boa Acrantophis madagascariensis
Human
Human Homo sapiens

Related Species 5

Diademed sifaka Propithecus diadema Shared Family
Verreaux's sifaka Propithecus verreauxi Shared Family
Eastern woolly lemur Avahi laniger Shared Family
Silky sifaka Propithecus candidus Shared Family
Coquerel's sifaka Propithecus coquereli Shared Family

Ecological Equivalents 4

Animals that fill a similar ecological role in their ecosystem

Diademed sifaka Propithecus diadema Large-bodied, diurnal, arboreal folivore in eastern Malagasy rainforests; overlaps strongly with the indri in canopy use and vertical clinging-and-leaping locomotion, and competes for leaves, flowers, and fruits.
Eastern woolly lemur Avahi laniger Arboreal folivore in the same family that uses similar forest strata and relies heavily on leaves. It is nocturnal, so while it partitions activity time, it remains ecologically similar in diet and forest dependence.
Black-and-white ruffed lemur Varecia variegata Large, canopy-dwelling rainforest lemur in eastern Madagascar. Overlaps in arboreal niche and in the use of ripe fruit and flowers, although ruffed lemurs are more frugivorous; they share habitat structure and some food resources.
Greater bamboo lemur Prolemur simus Large-bodied, arboreal/semiterrestrial lemur of eastern Madagascar's humid forests. Occupies a broadly similar forest niche but specializes on bamboo, representing a dietary specialization within the same habitat.

Classification And Evolution

The Indri is the largest species of Lemur found only on the island of Madagascar. Although they resemble ancestral primates, Indri actually shares a more common ancestor with the Loris and most likely evolved from smaller animals that came to the island from Africa during the early Eocene era, about 50 million years ago. Because there were no other primates to compete with, the Lemur species soon adapted to reside in various habitats, which created a diverse range of distinct species.

In Madagascar, the Indri is also called the babakoto which means ancestor of man or little father. The Indri is safe from consumption by the locals as there is a certain taboo over ingesting this animal since the native people believe that the Indri (with its lack of visible tail) resembles their ancestors. As a result, the Indri receives a bit of protection in some parts of their native environments.

Anatomy And Appearance

Indris are the largest of all living Lemur species today with some individuals reaching nearly a meter in height. The average Indri, however, tends to be between 23.62 inches and 31.69 inches tall with a tail of just 1.96 inches (all other Lemurs have tails that are around the same length as their bodies). The Indri is an animal with a dense coat of black silky fur with a varying number of white patches depending on the geographic region. Their toes and fingers are very dexterous and are good for grasping and their long hind legs aid them in leaping up to 10 meters between vertical branches in the forest. The yellow eyes of the Indri face forward to help them to judge the distance before making a jump.

Distribution And Habitat

The Indri, like all Lemurs, is only found on the island of Madagascar in tropical forests and lowland jungles. As arboreal animals, they spend the majority of their lives, sleeping, eating, and mating high up in the trees. Due to the increase in logging and the clearing of land for agriculture, the Indri is now only found in small areas of protected forest in Eastern Madagascar. Although exact numbers are not entirely clear, it is thought that there are less than 10,000 Indri left in Madagascar, which means that the species is severely threatened in its natural habitat.

Behavior And Lifestyle

The Indri is a sociable animal, living in small family units of between 2 – 6 individuals, that consists of a male and female pair with their young. In the primate family, the Lemur is unique because it is the females who are the dominant sex, which means they feed first while the males defend their territory. Indris have a loud communication system. They call to each other through a series of eerie wails, both to unite families and also to mark their territory, which can be heard up to 1.25 miles away. They also urinate along borders to mark out their patch. Lemurs have an excellent sense of smell which enables them to sniff out these markings easily and they can avoid confrontation.

Reproduction And Life Cycles

Females Indris don’t tend to reach sexual maturity until they are 8 or 9 years old when they are able to have one infant every two or three years. The babies are usually born in May or June after a gestation period of between 4 and 5 months. The Indri infant clings onto the belly of its mother for the first few months of life, when it then moves around onto her back. By the time Indri babies are around 8 months old, they are independent of their mother but generally remain with her until the age of 2 or 3. Sadly, half of all Indri babies are thought to die before the age of 2, usually due to sickness or injury. Although adult Indris have been known to get well into their twenties, most live for between 15 and 18 years.

Diet And Prey

The Indri is an herbivorous and folivorous animal, unlike many other primates that will eat almost everything they see. Indris are diurnal animals and are most active during the day which is when they hunt for food, both on the ground and in the trees. When it comes to eating, females get to choose first and seem to have a greater preference for younger leaves than males, which they are often found foraging for. These young leaves make up a vast majority of the Indri’s diet along with seeds, flowers, and fruits. It is thought that the Indri has a diet that is predominantly made up of vegetation that comes from the trees but they are known to eat a wide variety of plant matter.

Predators And Threats

Indris are thought to have different danger signals for each predator.

Since the Indri lives high up in the trees, it is generally safe from many ground-dwelling predators, although there are a number of animals that have no issues reaching where the Indri is. The native puma-like giant mongoose, the Fossa is the main predator of the Indri. Incredibly agile and primarily a tree-dwelling mammal, it has evolved to catch Lemurs. Other predators of the Indri include large birds of prey like hawks, and reptiles, including the boa constrictor, all of which the Indri are thought to have different danger signals for. One of the largest threats to the population of the Indri is habitat loss, as hundreds of acres of natural habitat are being cleared daily.

Interesting Facts And Features

The largest existing Lemur today, the Indri is most closely related to the more primitive primate species which includes Bushbabies, Lorises, and Pottos. Despite the fact that there are over 100 species of Lemurs and their sub-species found today, the Indri is the only remaining species in its genus. Before deforestation ravaged the island, it is believed that there was a different population of Indri that occupied nearly every ridge in the eastern forests of Madagascar. The Indri has a different color that varies throughout populations, with individuals located further south thought to have more patches of white, while those geographically north tend to be darker.

Relationship With Humans

Until industry started to take an interest in Madagascar’s natural resources, the Indri seemed to have a relatively peaceful relationship with the native people and were not eaten by them. Today however, reports of non-locals hunting the Indri are of great concern to conservationists, particularly at a time when populations are being so devastatingly affected by the destruction of their natural environments. Indri populations are now thought to be drastically low, as the Indri can only be found in protected forest regions (where logging and land devastation still occurs).

Conservation Status And Life Today

While the exact number of Indri inhabiting Madagascar today is not clear, it is believed that there are only up to 10,000 individuals left in the wild. However, there are other estimates that prove more concerning and claim that there may be as few as 1,000 Indri left. As of now, they are a protected species with the listing as critically endangered. Unfortunately, the Indri does not do well in captivity so any captive breeding programs to try and rehabilitate the dying populations are not likely to be successful.

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Chinese
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Sources

  1. David Burnie, Dorling Kindersley (2011) Animal, The Definitive Visual Guide To The World's Wildlife / Accessed January 7, 2011
  2. Tom Jackson, Lorenz Books (2007) The World Encyclopedia Of Animals / Accessed January 7, 2011
  3. David Burnie, Kingfisher (2011) The Kingfisher Animal Encyclopedia / Accessed January 7, 2011
  4. Richard Mackay, University of California Press (2009) The Atlas Of Endangered Species / Accessed January 7, 2011
  5. David Burnie, Dorling Kindersley (2008) Illustrated Encyclopedia Of Animals / Accessed January 7, 2011
  6. Dorling Kindersley (2006) Dorling Kindersley Encyclopedia Of Animals / Accessed January 7, 2011
  7. David W. Macdonald, Oxford University Press (2010) The Encyclopedia Of Mammals / Accessed January 7, 2011
  8. Indri Conservation / Accessed January 7, 2011
  9. About Primates / Accessed January 7, 2011
  10. Indri Behaviour / Accessed January 7, 2011
  11. Indri Habitat / Accessed January 7, 2011
  12. Indri Rehabilitation / Accessed January 7, 2011
Melissa Bauernfeind

About the Author

Melissa Bauernfeind

Melissa Bauernfeind was born in NYC and got her degree in Journalism from Boston University. She lived in San Diego for 10 years and is now back in NYC. She loves adventure and traveling the world with her husband but always misses her favorite little man, "P", half Chihuahua/half Jack Russell, all trouble. She got dive-certified so she could dive with the Great White Sharks someday and is hoping to swim with the Orcas as well.
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Indri FAQs (Frequently Asked Questions)

Indris are Herbivores, meaning they eat plants.