UPSC Prelims 2013 Q10: Environment & Ecology – Biodiversity & Conservation
Consider the following animals:
1. Sea cow
2. Sea horse
3. Sea lion
Which of the above is/are mammal/mammals?
- (a) 1 only
- (b) 1 and 3 only
- (c) 2 and 3 only
- (d) 1, 2 and 3
Answer: (b) 1 and 3 only
Explanation
Which of these 'sea' animals are mammals?
| Animal | Mammal? | What it is |
|---|---|---|
| 1. Sea cow | Yes | Dugong and manatee; plant-eating marine mammals |
| 2. Sea horse | No | A small bony fish (genus Hippocampus); the male carries the eggs |
| 3. Sea lion | Yes | A marine mammal with ear flaps; related to seals |
Marks of a mammal:
| Feature | Detail |
|---|---|
| Milk | Young are fed on mother's milk |
| Breathing | With lungs; must come up for air |
| Body heat | Warm-blooded |
| Birth | Most give birth to live young |
Other marine mammals: whales, dolphins, seals, walruses, sea otters.
Not mammals: sea horse, starfish, jellyfish.
Answer: (b) 1 and 3 only.
Why each option is right or wrong
- (a) Incorrect. The sea lion is also a mammal.
- (b) CORRECT. The sea cow and sea lion are mammals; the sea horse is a fish.
- (c) Incorrect. The sea horse is a fish, and the sea cow is left out.
- (d) Incorrect. The sea horse is not a mammal.
Key point
Marine mammals: sea cow (dugong, manatee), sea lion, seal, whale, dolphin. Sea horse is a bony fish in which the male carries the young.
Remember
Sea cow and sea lion = mammals; sea horse = fish.
Common mistakes
- Taking the names literally: a sea horse is not a horse.
- Forgetting that the dugong is the sea cow of Indian waters.
- Thinking all animals living in the sea are fish.
Exam tip
Names mislead: starfish, jellyfish and sea horse. Only the sea horse is truly a fish; none is a mammal.
Sources
- NCERT Class XI — Biology, Ch 4 (Animal Kingdom: Pisces and Mammalia)
- Zoological Survey of India — Marine mammals of India