Classification – Odd one out (gender of animal terms): Which term is unlike the others: Mare, Stag, Lioness, Bitch?

Introduction / Context:
This verbal classification item relies on the grammatical gender of animal terms. Three of the options are explicitly female terms; one is explicitly male. Identifying the gender encoded in common zoological vocabulary isolates the outlier unambiguously.

Given Data / Assumptions:

• Mare: adult female horse.
• Stag: adult male deer.
• Lioness: adult female lion.
• Bitch: adult female dog.

Concept / Approach:
Map each word to its sex-specific meaning. If three denote female animals and one denotes a male animal, the male term stands out as the odd one.

Step-by-Step Solution:
Mare → female.Lioness → female.Bitch → female.Stag → male.

Verification / Alternative check:
Check for any polysemy that could confuse the mapping (e.g., slang). In standard zoological English, the above definitions are consistent and widely accepted, giving a unique 3-to-1 split.

Why Other Options Are Wrong:

• Mare, Lioness, and Bitch are all female-specific terms and therefore belong to the same category.

Common Pitfalls:
Assuming “bitch” is unacceptable as a technical term; within zoology, it is standard for a female dog, which is the intended sense here.

Final Answer:
Stag