LAC ALAOTRA GENTLE LEMUR
Hapalemur alaotrensis
Geographic Distribution and Habitat
The Lac Alaotra gentle lemur, also known as Alaotra reed lemurs, Alaotran gentle lemurs, Lac Alaotra bamboo lemurs, Lake Alaotra gentle lemurs, and the bandro in Malagasy, lives in the papyrus and reed beds around Lake Alaotra, the largest lake in Madagascar. This species is the only primate in the world that lives primarily in marshlands.
The common ancestor of all lemurs arrived in Madagascar about 50 million years ago. They likely “rafted” from mainland Africa to Madagascar, stranded on pieces of driftwood swept away by the current.
The Lac Alaotra gentle lemur, also known as Alaotra reed lemurs, Alaotran gentle lemurs, Lac Alaotra bamboo lemurs, Lake Alaotra gentle lemurs, and the bandro in Malagasy, lives in the papyrus and reed beds around Lake Alaotra, the largest lake in Madagascar. This species is the only primate in the world that lives primarily in marshlands.
The common ancestor of all lemurs arrived in Madagascar about 50 million years ago. They likely “rafted” from mainland Africa to Madagascar, stranded on pieces of driftwood swept away by the current.
Lac Alaotra Gentle Lemur range, circled in red, IUCN 2020.
Lac Alaotra bamboo lemur rage zoomed-in, IUCN 2020
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Size, Weight, and Lifespan These lemurs are on average 16 in (40 cm) long with a tail of roughly equal length. They can range anywhere from 2.2 to 3.5 lbs (1–1.6 kg). Females are usually slightly bigger than their male counterparts. Gentle lemurs can live up to 23 years. Appearance
The Lac Alaotra gentle lemur has a thick coat of brown and grey fur with a short, round head. His long tail is used to keep balance as the lemur walks from reed to reed. 
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What Does It Mean?Anogenital:
Relating to the anus and genital region. Ecosystem: A biological community of interacting organisms and their physical environment. Endemic: Native or restricted to a certain area or country. Gestation Period: The time of pregnancy from conception until birth. |
Diet
Despite being members of the bamboo lemur genus, Lac Alaotra gentle lemurs do not eat bamboo. In fact, they are the only bamboo lemurs who do not feed on bamboo. Their diet depends heavily on the stems and leaves of papyrus plants, which make up most of their habitat. In total, Lac Alaotra gentle lemurs feed on 17 different plants, almost entirely feeding on younger plants.
Despite being members of the bamboo lemur genus, Lac Alaotra gentle lemurs do not eat bamboo. In fact, they are the only bamboo lemurs who do not feed on bamboo. Their diet depends heavily on the stems and leaves of papyrus plants, which make up most of their habitat. In total, Lac Alaotra gentle lemurs feed on 17 different plants, almost entirely feeding on younger plants.
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Behavior and Lifestyle
Bandros are very territorial and have conflicts with outside groups. On average, a group of gentle lemurs will hold a territory of about 2 hectares, usually overlapping with other group territories. They usually walk on all 4 limbs but will also leap from location to location like certain other lemurs (sifakas, indri, etc.). Daily Life and Group Dynamics
Gentle lemurs are cathemeral, meaning they are active during both day and night. Specifically, they are most active at sunrise and sunset. Groups typically feature 3 to 5 individuals, usually a mating pair and their offspring. Occasionally there are other adults present as the Lac Alaotra gentle lemur is not entirely monogamous. |
Fun FactsMany scientists consider the Lac Alaotra bamboo lemur to be a subspecies of the eastern lesser bamboo lemur. Although the 2 groups have very different behaviors, genetic analysis has shown the 2 may actually be the same species. |
Communication
The Lac Alaotra gentle lemur relies on vocal, visual, and scent communications.
This animal has at least 9 basic calls, ranging from purrs to chitters to squeals. These calls are made as warnings, threats, and bond enhancers.
Visual communications are generally reserved for intergroup conflicts, where individuals may run around in a circle and bluff charging (rushing toward the rival before jumping back at the last moment).
Scent marking is also usually saved for conflicts with other groups. Males use the brachial glands on their arms while females use their anogenital glands to scent mark. Often, they will engage in tail scent marking in which they rub their glands on their tail and wave it in the rival’s direction.
Reproduction and Family
Mating season for the gentle lemur occurs in June and July. The bandro’s gestation period is about 145 days. Ideally, females will give birth once every year. Mothers carry their young in their mouth until the babies are strong enough to cling to the mother’s back after a week or two. Babies are weaned after about 16 weeks and develop rather quickly relative to other primate species.
At 2 years old, Lac Alaotra gentle lemurs reach adulthood and will leave to start a family of their own.
Mating season for the gentle lemur occurs in June and July. The bandro’s gestation period is about 145 days. Ideally, females will give birth once every year. Mothers carry their young in their mouth until the babies are strong enough to cling to the mother’s back after a week or two. Babies are weaned after about 16 weeks and develop rather quickly relative to other primate species.
At 2 years old, Lac Alaotra gentle lemurs reach adulthood and will leave to start a family of their own.
Photo credit: Mark Kent/Creative Commons
Ecological Role
Lac Alaotra gentle lemurs are vital to the health and ecological balance of the marshes that they inhabit.
Lac Alaotra gentle lemurs are vital to the health and ecological balance of the marshes that they inhabit.
Conservation Status and Threats
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The International Union for Conservation of Nature lists the Lac Alaotra gentle lemur as Critically Endangered (IUCN, 2018). Since 1990, their population has declined by over 80%. The total species population has fallen from an estimated 11,000 to about 2,500 gentle lemurs.
In the 2016-2018 and the 2018-2020 Primates in Peril reports, the Lac Alaotra gentle lemur was listed as one of the 25 most endangered primate species in the world. The report stated that the total population may be below 1,000 individuals today. The biggest threat to these lemurs is the conversion of their habitat to rice fields. While the bandro’s remaining habitat is not suitable for rice cultivation due to seasonal flooding, the IUCN notes that a major drainage project could open up most of the lemur’s remaining habitat for future cultivation. Bandro habitat is also destroyed to make room for fishing. The fishing industry has had a detrimental effect on Lake Alaotra ecology. No endemic fish have been caught from the lake since 2001. In other words, the lake may be entirely made up of invasive species. Over the last few decades, several thousand Lac Alaotra gentle lemurs have been killed by hunters and captured for the pet trade. Birds of prey, fossas, and snakes are the bandro’s natural predators. |
Conservation Efforts
As with all lemurs, much of the Lac Alaotra gentle lemur’s conservation hopes depend on Madagascar’s economic situation. Madagascar has a GDP (gross domestic product) per capita of $1,600, ranking them 217th out of the 228 listed countries. Conservation issues often take a backseat when local citizens are struggling to make ends meet.
Madagascar Wildlife Conservation has multiple initiatives based around Lake Alaotra, one of which is Camp Bandro. Camp Bandro is an ecotourism venture that educates people on the local ecosystem while also providing an alternate source of income for local villages, thus giving a financial incentive for citizens to protect the lake and its inhabitants.
The Durrell Wildlife Conservation Trust helped secure 42,478 hectares of protected area around Lake Alaotra in 2007.
As with all lemurs, much of the Lac Alaotra gentle lemur’s conservation hopes depend on Madagascar’s economic situation. Madagascar has a GDP (gross domestic product) per capita of $1,600, ranking them 217th out of the 228 listed countries. Conservation issues often take a backseat when local citizens are struggling to make ends meet.
Madagascar Wildlife Conservation has multiple initiatives based around Lake Alaotra, one of which is Camp Bandro. Camp Bandro is an ecotourism venture that educates people on the local ecosystem while also providing an alternate source of income for local villages, thus giving a financial incentive for citizens to protect the lake and its inhabitants.
The Durrell Wildlife Conservation Trust helped secure 42,478 hectares of protected area around Lake Alaotra in 2007.
References:
- https://www.arkive.org/alaotran-gentle-lemur/hapalemur-alaotrensis/
- http://www.bbc.co.uk/nature/life/Lac_Alaotra_Bamboo_Lemur
- http://www.iucnredlist.org/details/9676/0
- http://pin.primate.wisc.edu/factsheets/entry/bamboo_lemur/taxon
- http://www.madagascar-wildlife-conservation.org/lake-alaotra/
- https://www.marwell.org.uk/zoo/explore/animals/4/alaotran-gentle-lemur
- https://www.globalwildlife.org/wp-content/uploads/2017/11/Primates-in-Peril-Top-25.pdf
- http://wildlife.durrell.org/animals/mammals/alaotran-gentle-lemur7/
- https://alltheworldsprimates.org/Members/Home/MasterPrimate/DataPage.aspx?taxa=diet&ttype=11&primate=34&cate=diet
- https://news.nationalgeographic.com/news/2010/01/100120-mammals-madagascar-rafting-lemurs/
- https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=122220&lvl=3&p=mapview&p=has_linkout&p=blast_url&p=genome_blast&lin=f&keep=1&srchmode=1&unlock
- https://www.cia.gov/library/publications/the-world-factbook/rankorder/2004rank.html
- “Bandro!” - https://www.youtube.com/watch?v=lgJLRg33L4E
Written by Eric Starr, April 2018
