Examples of animals with mammary glands include the following except

Step 1: Analyze the question The question asks which animal does NOT have mammary glands. Look for the animal that is not a mammal.

Step 2: Explain the concept Mammary glands are milk-producing glands found only in mammals (class Mammalia). Females use them to feed their young. Other typical mammal features include:

• Body covered with hair or fur
• Warm-blooded (endothermic)
• External ears (pinnae) in most species
• Live birth in most species (the exceptions are the monotremes, which lay eggs)

Birds belong to class Aves. They have feathers and lay eggs, and they do not have mammary glands. They feed their chicks by other means, not with milk.

Step 3: Go through the options

• A. Cow: a mammal, has mammary glands (udder). ✔
• B. Goat: a mammal, has mammary glands. ✔
• C. Pig: a mammal, has mammary glands (sows nurse piglets). ✔
• D. Hen: a bird, no mammary glands. ✘

Step 4: Answer The hen is the exception, so the answer is D.

Tip: In "all of the following except" questions, find the odd one out. Here three options are mammals and one is a bird. Remember: mammary glands = mammals, and feathers plus egg-laying with no milk = birds.