Mammalia is a class within the subphylum Vertebrata. Which of the following animals is classified under the class Mammalia?

Appeared in: DSSSB 6 September 2024

Explanation

Bats are classified under the class Mammalia.
They exhibit key mammalian traits: they are warm-blooded, have hair, give birth to live young (viviparity), and females possess mammary glands to produce milk for their offspring.
Bats are unique as they are the only mammals capable of sustained flight.

Option A: Crocodiles belong to the class Reptilia, not Mammalia. They are cold-blooded, have scales, and lay eggs.
Option B: Snakes are also classified under the class Reptilia. Like crocodiles, they are cold-blooded, covered in scales, and lay eggs.
Option D: Penguins belong to the class Aves (birds). While they are warm-blooded, they have feathers, lay eggs, and lack mammary glands.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Biological classification of vertebrates, specifically identifying an animal belonging to the class Mammalia as background academic context rather than a clinical decision trigger.
Understanding animal classifications is foundational for epidemiology, particularly in tracking zoonotic diseases (diseases transmitted from animals to humans).
Bats are significant reservoirs for several viruses that can infect humans, including Rabies virus and various Coronaviruses. Nurses should be aware of potential exposure risks in patients who report contact with bats.
A patient history that includes animal contact, especially with wildlife like bats, should prompt a nurse to consider specific infectious diseases and inquire about bites or scratches.

How to Approach the Question

First, identify the core concept of the question, which is animal classification, specifically the characteristics of the class Mammalia.
Recall the defining features of a mammal: warm-blooded, has hair or fur, gives birth to live young, and produces milk via mammary glands.
Systematically evaluate each option against these mammalian characteristics.
Analyze 'Crocodile' and 'Snake': They are cold-blooded, have scales, and lay eggs, which are features of reptiles.
Analyze 'Penguin': It is warm-blooded but has feathers and lays eggs, which are features of birds (Aves).
Analyze 'Bat': It is warm-blooded, has fur, gives birth to live young, and produces milk. These features align perfectly with the definition of a mammal.

Concept Tested & Keywords

Concept Tested: Biological classification of vertebrates, specifically identifying an animal belonging to the class Mammalia.
Stem keywords: Mammalia, class, subphylum Vertebrata, animal
Lead-in keywords: Which of the following

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Practise the full DSSSB 6 September 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.