Question

Which one of the following animals belongs to the oviparous mammal group?

• A. Macropus
• B. Pteropus
• C. Rattus
• D. Platypus

Hint:

There are only five living species of monotremes in the world: the duck-billed platypus and four species of echidna. If you see "egg-laying mammal" on an exam, the answer will almost certainly be one of these two.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The question asks to identify an oviparous (egg-laying) mammal. Mammals are overwhelmingly viviparous (giving live birth), but there is one small, ancient group that lays eggs.

Step 2: Detailed Explanation:
- The class Mammalia is divided into three main groups based on reproductive strategy: 1. Monotremes: These are the only oviparous mammals. This group includes the platypus and echidnas. 2. Marsupials: These are viviparous mammals that give birth to a very underdeveloped (altricial) young, which then completes its development in a pouch. Examples include kangaroos ({Macropus}), koalas, and opossums. 3. Placental Mammals (Eutherians): These are viviparous mammals where the fetus develops fully inside the mother's uterus, nourished by a placenta. This is the largest group of mammals, including bats ({Pteropus}), rats ({Rattus}), and humans. - Analyzing the options: - (A) {Macropus} is a kangaroo, a marsupial. - (B) {Pteropus} is a flying fox (a type of bat), a placental mammal. - (C) {Rattus} is a rat, a placental mammal. - (D) {Platypus} is a monotreme and is famous for being an egg-laying mammal.
Step 3: Final Answer:
The platypus is the oviparous mammal among the choices. Therefore, option (D) is correct.