INDRI
Indri

Like other prosimians, Indris are a species of lemur that live only on the island of Madagascar. The largest of the lemurs, Indris have the longest legs yet the shortest tail. Because of its lack of visible tail, native people call the Indri the babakoto, meaning little father or ancestor of man. As such there is a taboo around viewing it as a source of meat, which affords the species some protection although, as all lemurs, it is endangered.

Indris use their long legs to leap, feet-first, across large gaps in the forest. Their large thumbs and big toes help them to hold on to branches while they are moving and feeding in the trees. Indris often feed upside-down, hanging by their legs. They eat fruit and leaves and sometimes they even eat soil. The soil is thought to remove toxins from their bodies that they ingest with the leaves. It also provides traces of minerals that they cannot get elsewhere. They have a special organ in their gut that helps them break down the tough cellulose in the leaves that they eat. In the mornings, the Indris use an organ in their larynx to make very loud calls to keep other Indris out of their territory. 

Indri geographic range map. Credit: Alex Dunkel (Maky) and IUCN

Indri Fun Facts:

• Local legend holds that Indris howl at dawn to mourn the loss of their tails, taken by black and white ruffed lemurs.
• Indris sing song battles and scent mark during territory disputes. 
• They make warning calls that specifically identify birds, thunder and airplanes. 
• From October to December Indris live lower in the canopy to avoid horse flies. 
• Group members urinate and defecate in synchronized fashion, all lined up on the same branch. 
• Females attack males that get too close to them while they sleep. 
• Indris sometimes eat soil, which may help detoxify poisons from their bodies that they ingest in leaves, or provide trace elements that their bodies need. 

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Distinguishing Features:

• Yellow-green eyes with reflective tapetum. Eyes are medium sized and foreward facing. 
  
• Large, furry, tufted, black ear on the top of the head. 
  
• Small short snouts with nostril position. 
• 30 teeth including molars for grinding. Dental comb for grooming. 
• Some Indris have white face rings and others have black face rings. 
  
• Indris have lyryngeal sacs to assist in their songs. 
  

• Arms are shorter than hind legs. 
  

• Short fingers with a long thumb. 
  
• They have a cecum with microflora to help break down cellulose in plant materials. 
  
• Legs are very long for leaping. 
  
• Bi-pedal locomotion on the ground. 
  
• The tail is not prehensile, and is very short. 
• Fur is very dense and its coloration is black and white and varies in pattern by individual. 
• Average body size and weight – 23.6 inches long and 15 lbs.
• Tail is very short in relation to the body. 

Diet and Lifestyle:

• Indris eat young leaves, fruit, seeds, buds and occasionally soil. 
  
• They thrive in the humid mountain forests of Madagascar.
• Indris are prosimians.
• Old World monkeys.
  
• Troop size is 2-6, monogamous one male-one female and offspring.

Behavior and Play:

• Females are dominant.
• Females are the primary parental caregivers, but juveniles will sleep with males after a year old. 
• Both genders migrate out of the troop during sexual maturity.
• Males actively defend territories through song battles and scent marking. 
• Young Indris play and wrestle with each other. 
• Grooming is done with hands and tooth comb and is reciprocal. 

Culture and Communication:

• Loud call in the early morning is used to designate territory. 
• Their “song” is a series of howls and cries. 
• Honks are used as a contact call. 
• Alarm calls are used for predator sightings. 
• Humming indicates movement in the group. Kissing and wheezing noises indicate fright. 
• Scent marking is done by males using genitals or cheek glands and saliva. 

    Threats and Conservation Status:

• IUCN categorizes Indris as Critically Endangered.*
• Deforestation is hurting this species.
• Indri are also hunted by some people. 
• Their habitat is protected by a ban on logging, but it has not stopped loggers in the area. 

​*Conservation status update May 2016

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Video of Indris calling to eachother courtesy of ARKive.org