Q. Consider the following animals:

1. Hedgehog
2. Marmot
3. Pangolin

To reduce the chance of being captured by predators, which of the above organisms rolls up and protects its vulnerable parts? (UPSC Prelims 2021)
Answer: 1 and 3
Notes: The correct answer is [D] 1 and 3. This question focuses on the specific defense mechanism of curling into a ball to protect soft underparts with a tough exterior.

• Hedgehog (Statement 1 – Correct): When threatened, a hedgehog uses its strong back muscles to curl into a tight ball. This tucks away its head, legs, and belly, leaving only its sharp, keratin-hardened spines (quills) exposed to the predator.
• Pangolin (Statement 3 – Correct): Known as the "scaly anteater," the pangolin is covered in large, overlapping scales made of keratin. When it senses danger, it rolls into a near-impenetrable ball, protecting its soft underside. Its tail is also used to wrap around the ball for extra security.
• Marmot (Statement 2 – Incorrect): Marmots are large ground squirrels. Their primary defense mechanism is not rolling into a ball; instead, they rely on loud, whistling alarms to warn the colony and then retreat quickly into deep underground burrows to escape predators.

Ecological Context: While both the hedgehog and pangolin share this "curling" behavior (an example of convergent evolution for defense), they belong to entirely different biological orders. The hedgehog is an insectivore, while the pangolin is the only mammal covered in true scales.