UPSC Prelims 2023 Q14: Nocturnal Fauna of the Western Ghats Explained
Consider the following fauna:
1. Lion-tailed Macaque
2. Malabar Civet
3. Sambar Deer
How many of the above are generally nocturnal or most active after sunset?
- Only one
- Only two
- All three
- None
Answer: (a) Only one
Statement-wise explanation
- 1: incorrect — The Lion-tailed Macaque (Macaca silenus) is diurnal: it is active by day and sleeps at night high in the trees. It lives in troops of about 10–20 animals in the tall evergreen rainforest canopy of the Western Ghats and feeds mainly on fruit. It is found only in the Western Ghats and is listed as Endangered on the IUCN Red List.
- 2: correct — The Malabar Civet, also called the Malabar large-spotted civet (Viverra civettina), is a solitary, shy and nocturnal carnivore. Like other civets of its genus, it forages on the ground at night. It is found only in the Western Ghats and is listed as Critically Endangered on the IUCN Red List, with fewer than 250 mature individuals estimated, and it has very few confirmed records.
- 3: incorrect — The official key counts the Sambar (Rusa unicolor) as not generally nocturnal. Field studies with camera traps show its activity peaking at dawn and dusk, which makes it crepuscular. Where it is not disturbed, it also feeds by day. Many standard references still describe it as 'nocturnal or crepuscular' (see the dispute note), so this is the statement where most candidates went wrong. Sambar is India's largest deer and is listed as Vulnerable on the IUCN Red List (since 2008).
How to eliminate
Basic knowledge settles two of the three animals. Monkeys and apes are almost all active by day. Among Old World monkeys only the owl monkey (a New World species) breaks the rule, so the Lion-tailed Macaque is diurnal. That rules out 'All three'. Civets are a well-known nocturnal family, so the Malabar Civet is nocturnal. That rules out 'None'. You are now choosing between 'Only one' and 'Only two', and the choice turns entirely on the Sambar. Option logic cannot decide it. You need the fact. The official key treats the Sambar as crepuscular (busiest at dawn and dusk) rather than 'generally nocturnal'. Remember that crepuscular and nocturnal are separate categories in UPSC's eyes. Watch the phrase 'generally nocturnal or most active after sunset': UPSC wanted animals whose peak activity is in full darkness.
Know more
Activity patterns of animals
Ecologists sort animals by the time of day they are most active:
| Pattern | Peak activity | Indian examples |
|---|---|---|
| Diurnal | Daylight | Lion-tailed Macaque, Nilgiri Langur, most birds, Nilgiri Tahr |
| Nocturnal | Night | Malabar Civet, Slender Loris, Indian Pangolin, owls, most bats |
| Crepuscular | Dawn and dusk | Sambar, Chital at the edges of the day, many deer and rabbits |
| Cathemeral | Irregular, day and night | Tiger (shifts with prey and disturbance) |
Activity patterns can change. Hunting, tourism and roads push many mammals towards night activity. Sambar living near people are often more nocturnal than Sambar in protected forests. This is why sources disagree about the species.
The Western Ghats link
Two of the three animals are Western Ghats endemics, meaning they are found nowhere else. The Western Ghats and Sri Lanka together form one of the world's 36 biodiversity hotspots.
| Species | Endemic to Western Ghats? | IUCN status | Activity |
|---|---|---|---|
| Lion-tailed Macaque | Yes | Endangered | Diurnal, lives in the canopy |
| Malabar Civet | Yes | Critically Endangered | Nocturnal, lives on the ground |
| Sambar | No (South and Southeast Asia) | Vulnerable | Crepuscular to nocturnal |
Other Western Ghats endemics that UPSC likes to ask about include the Nilgiri Tahr, the Nilgiri Langur, the Malabar Grey Hornbill and the Purple Frog. For each animal you revise, note three things: where it lives, its IUCN status, and whether it is active by day or night.
NCERT Concepts to Revise
- Biodiversity hotspot: Two of the three animals are found only in the Western Ghats hotspot, so knowing what endemism means helps place them.
- IUCN Red List: Each animal has a different Red List status, a common second angle for questions about the same species.
- Threatened species: All three species fall under the 'threatened' umbrella, which is useful when UPSC reframes this question by conservation status.