What Makes a Mammal a Mammal?
Think about a tiny brown bat fluttering through the twilight sky, an enormous blue whale gliding through the icy ocean depths, and a spotted leopard leaping through tree branches. At first glance, these creatures seem completely different. One flies through the air, one swims in the sea, and one prowls on land. Yet, all three belong to the very same scientific family. They are all mammals.
Scientists classify animals into groups based on shared physical traits and life cycles. Mammals form one of the most diverse groups of vertebrates, or animals with backbones. Despite their amazing variety in size, shape, and habitat, every mammal shares several key characteristics that set them apart from birds, reptiles, amphibians, and fish.
Hair and Fur
- vertebrates:
- Animals that have a backbone.
- insulation:
- A material or layer that prevents heat from escaping, keeping an animal warm.
- mammary glands:
- Special parts of a female mammal's body that produce milk to feed babies.
- endothermic:
- Able to create and regulate heat inside the body; warm-blooded.
- placenta:
- An internal organ that provides food and nourishment to an unborn baby inside its mother.
- marsupials:
- Mammals whose underdeveloped babies continue growing inside a mother's pouch.
- monotremes:
- A rare group of mammals that lay eggs rather than giving birth to live young.
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Preview questions from this passageShowHide
- 1What is the main idea of the passage?
- 2Why does the author begin the article by describing a bat, a blue whale, and a leopard?
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About this explanatory article passage for Upper Elementary
“What Makes a Mammal a Mammal?” is a explanatory article reading passage about Mammals, written for Upper Elementary. It takes about 4 minutes to read (600 words) and comes with an interactive quiz and a printable worksheet with comprehension questions and an answer key.