biology

Nilgiri langur

Nilgiri langur is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Nilgiri langur rather than just read about it. In short: The Nilgiri langur (Semnopithecus johnii) is an Asian langur of the Old World monkey. It has glossy, black fur and an orangey-golden brown, hair-like mane on its head.

Key takeaways

Nilgiri langur belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Nilgiri langur to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Nilgiri langur from memory before moving on to harder problems.

Reference excerpt

The Nilgiri langur (Semnopithecus johnii) is an Asian langur of the Old World monkey. It has glossy, black fur and an orangey-golden brown, hair-like mane on its head. Females have a white patch of fur on the inner thigh. It typically lives in troops of nine to ten individuals, with or without offspring, depending on seasonality. Its diet consists of fruits, shoots and leaves. It is listed as vulnerable on the IUCN Red List and is threatened by habitat destruction and poaching for its body parts, thought to supposedly contain aphrodisiac properties.

Taxonomy and classification The classification of the Nilgiri langur has been disputed. Traditionally it has been placed within the genus Trachypithecus based on morphological similarities such as cranial morphology and neonatal pelage color, and within the Trachypithecus vetulus group within Trachypithecus based on a presumed close relationship with the purple-faced langur (Semnopithecus vetulus), which had formerly been classified as T. vetulus. DNA and other evidence suggests that the Nilgiri and purple-faced langurs are more closely related to the gray langurs, and have thus been reclassified within the genus Semnopithecus.

Description Adult males have a head-to-body length of 78–80 cm (31–31 in) and adult females of 58–60 cm (23–24 in); their tails are 68.5–96.5 cm (27.0–38.0 in) long. Males weigh 9.1–14.8 kg (20–33 lb) and females 10.9–12 kg (24–26 lb).

Distribution The Nilgiri langur is native to the Nilgiri Hills of South India, where it occurs at elevations of 300–2,000 m (980–6,560 ft) in the states of Karnataka, Kerala and Tamil Nadu. It has been sighted in Agasthyamala Biosphere Reserve, Aliyar Forest Reserve, Anamalai Tiger Reserve, Bandipur National Park, Eravikulam National Park, Idamalayar Reserve Forest, Mudumalai National Park, Mukurthi National Park, Mundanthurai Tiger Reserve, Nelliampathi, Periyar National Park, Shendurney Wildlife Sanctuary and Silent Valley National Park.

Behaviour and ecology The gestation period is not precisely known but assumed to be 200 days.

References

External links ARKive - images and movies of the Nilgiri langur (Semnopithecus johnii)

Illustrations

Worked examples

Example 1 — a first encounter with Nilgiri langur

Start with the simplest possible case. Write down what Nilgiri langur claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nilgiri langur before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nilgiri langur ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nilgiri langur

In research: Nilgiri langur appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Nilgiri langur in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Nilgiri langur is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arboreal mammals, Endemic fauna of the Western Ghats, Fauna of the Western Ghats, so understanding it makes those chapters shorter.
In everyday life: Look for Nilgiri langur outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Nilgiri langur in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Nilgiri langur means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Nilgiri langur out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Nilgiri langur in simple terms?

The Nilgiri langur (Semnopithecus johnii) is an Asian langur of the Old World monkey. It has glossy, black fur and an orangey-golden brown, hair-like mane on its head.

Why does Nilgiri langur matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nilgiri langur?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nilgiri langur.