Official UPSC Format

With respect to the Western Hoolock Gibbons, which of the following statements is/are correct?
1. A Sanctuary in North-east India is home to this ape species listed as Endangered in the International Union for Conservation of Nature (IUCN) Red List.
2. They have specialized brachiation and can easily swing between trees.
3. They possess a strong and heavy build like gorillas, yet are remarkably agile tree climbers.
Select the answer using the code given below:

1. A Sanctuary in North-east India is home to this ape species listed as Endangered in the International Union for Conservation of Nature (IUCN) Red List.

2. They have specialized brachiation and can easily swing between trees.

3. They possess a strong and heavy build like gorillas, yet are remarkably agile tree climbers.

⚡ Quick Recall Snippet

The Western Hoolock Gibbon is the only ape species found in India, specifically protected in sanctuaries in the Northeast. Listed as Endangered by the IUCN, they are 'lesser apes' known for their slender, lightweight builds (weighing only 6-9 kg), which allows them to traverse the forest canopy swiftly via brachiation.

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Detailed Solution & Authority Citations

Correct Answer is Option B
Let us analyze the biology and conservation status of India's only ape species:
  • Statement 1 is Correct: Native to the dense forests of North-east India, they are protected in reserves like the Hollongapar Gibbon Sanctuary in Assam. Due to severe habitat fragmentation, the Western Hoolock Gibbon is officially classified as Endangered on the IUCN Red List.

  • Statement 2 is Correct: They are highly specialized canopy-dwellers. Their primary mode of locomotion is brachiation—using their disproportionately long arms to swing suspended beneath tree branches, allowing them to traverse the forest at high speeds.

  • Statement 3 is Incorrect: Taxonomically, gibbons are classified as "lesser apes" (family Hylobatidae), fundamentally distinct from "great apes" like gorillas. They do not possess a strong, heavy build. To facilitate brachiation on fragile upper-canopy branches, they are extremely slender and lightweight, typically weighing only between 6 to 9 kilograms.
    • Conclusion: Statements 1 and 2 provide accurate ecological and biological data.

    🚨 The Examiner's Trap

    The examiner uses the word 'ape' to trigger a cognitive bias. Because popular culture associates 'apes' with massive creatures like gorillas or King Kong, candidates might assume all apes have a 'strong and heavy build,' leading them to falsely validate Statement 3.

    Active Recall Flashcard

    Tap to Flip

    What specialized term describes the primary mode of locomotion used by Hoolock Gibbons to swing from tree branch to tree branch?

    Brachiation.

    Concept Flow Mapping

    Western Hoolock Gibbon
    Has Conservation Status
    Endangered (IUCN)
    Western Hoolock Gibbon
    Uses Locomotion
    Brachiation
    Western Hoolock Gibbon
    Is Classified As
    Lesser Ape

    Logic Quest

    "Why must gibbons be lightweight?"

    Not analyzing core concepts like Morphology and Conservation of Indian Primates through the lens of Previous Year Questions is a serious miss-out. This PYQ engine is specifically designed to help you decode the examiner's mindset and master highly probable Environment & Ecology questions for your upcoming Prelims.