François' Langur Fact File
Appearance
The Francois langur is a primate covered with black fur across the entire body except for a white stripe running from the mouth to the eyes. On top of the head is a pointed crest of fur.
Above the eyes is a white crest which looks like an eyebrow.
A white tip is also present at the end of the long tail which is non-prehensile. This tail may make up as much as 90cm (35.4in) of their length.
Females and males can be told apart as females have a white pubic patch of fur.
Males tend to be larger than the female Francois langur. On average their body will measure 56cm (22in) long and average weights of 5.5 to 7.9kg (12 to 17.4lbs).
Diet
The Francois langur is a herbivore which primarily feeds on leaves. This is supplemented with fruit, bark, shoots and flowers.
Their special chambered stomach is used to help digest the tough leaves which provide little nutrients while being tough to digest. Bacteria line the stomach and aid in the process of digesting their food.
As their food provides such small amounts of energy much of the day is spent resting as the body works to break down their food.
Scientific Name
Trachypithecus francoisi
Conservation Status
Endangered
Weight
5.5-7.9kg (12-17.4lbs)
Length
56cm (22in)
Lifespan
26 years
Diet
Herbivorous
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Range
Asia is the native home of the Francois langur. Here they live in China and Viet Nam.
Habitat
Their make their home in tropical and subtropical rainforests and limestone hills.
Reproduction
Breeding takes place throughout the year though a peak is present in autumn and winter.
Francois langurs live in groups with a single male which will mate with multiple females during the same breeding season. Females tend to initiate the breeding behavior in this species.
At birth a young Francois langur is colored orange and fully furred. This makes them easier for other group members to see. Young are born after a 6 to 7 month gestation period.
Francois langurs engage in alloparenting (also called aunting) which involves a female helping to care for the offspring of other females. This behavior allows the mother to forage while the baby is safe with another family member.
Sexual maturity is reached between 4 and 5 years old.
Behavior
Males produce a hoarse vocalization which is used to defend their territory. Females vocalize using a range of barks, grunts and squeals.
Francois langurs are social primates forming groups of up to 12 individuals. Groups are led by a single male. Occasionally he will be challenged for leadership and may be ousted by a male.
These primates are primarily arboreal and spend much of their time in the trees. They can move around by launching themselves from one tree to another.
Predators and Threats
Francois langurs are threatened through logging and the expansion of agriculture.
They may be captured for use as pets or to be made in to traditional medicines. In parts of their range they are targeted for a specialized 'black ape wine' which is specifically made with the Francois' langur.
Human activity seems to prevent them expanding their range in to new areas.
Quick facts
The Francois langur is considered an old world monkey which describes species from Africa and Asia.
Francois langurs are known by a range of other names including the capped leaf monkey, Tonkin leaf monkeys, brown-ridge langur or black leaf monkey.
The challenging habitat of the Francois langur has made studying them difficult.
Photo Credits
Top
Dps austin, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
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Bottom
larsjuh, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
References
Belfastzoo.co.uk. 2021. The Zoo | François langur. [online] Available at: <http://www.belfastzoo.co.uk/animals/francois-langur.aspx> [Accessed 24 April 2021].
Lincoln Park Zoo. 2021. Francois' Langur - Lincoln Park Zoo. [online] Available at: <https://www.lpzoo.org/animal/francois-langur/> [Accessed 24 April 2021].
Philadelphia Zoo. 2021. Francois's langur – Philadelphia Zoo. [online] Available at: <https://philadelphiazoo.org/animals/francois-langur/> [Accessed 24 April 2021].
Ris, L. 2004. "Trachypithecus francoisi" (On-line), Animal Diversity Web. Accessed April 24, 2021 at https://animaldiversity.org/accounts/Trachypithecus_francoisi/
Eprc.asia. 2021. François’ Langur – Endangered Primate Rescue Center . [online] Available at: <https://www.eprc.asia/francois-langur/> [Accessed 25 April 2021].
Nadler, T., Quyet, L.K., Covert, H. & Long, Y. 2020. Trachypithecus francoisi. The IUCN Red List of Threatened Species 2020: e.T39853A17958817. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T39853A17958817.en. Downloaded on 24 April 2021.
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