The water bear: tiny but tough: stretch · Grade 5

The passage and its 8 questions

Directions: Read the passage carefully. Then answer the questions in full sentences.

• If you scoop up a clump of damp moss and look at it under a microscope, you might meet one of the toughest creatures on Earth. It has eight stubby legs tipped with tiny claws, and it lumbers along like a chubby bear. Scientists call it a tardigrade, but many people prefer its nickname: the water bear.
• Water bears are microscopic. Most are less than one millimeter long, so you need a microscope to see them clearly. Even so, they live almost everywhere: in moss and soil, in lakes and oceans, and even on icy mountaintops.
• What makes water bears remarkable is how much they can endure. When their home dries out, a water bear pulls in its legs, curls into a tiny ball and loses almost all the water in its body. In this dormant state, its body nearly stops working. It can stay this way for years. Add a few drops of water, and the water bear may revive within hours and stroll away as if nothing had happened.
• Scientists have tested just how resilient these creatures are. In laboratories, dried-out water bears have survived temperatures far colder than any winter on Earth. In 2007, scientists even sent some into orbit aboard a satellite. Some of them survived the airless vacuum of space. Back on Earth, a few even laid eggs that hatched.
• Still, water bears are not invincible. When they are active and full of water, they are quite vulnerable, and too much heat can harm them. Their real superpower is knowing when to pause and wait for better days.
• 1. Name three places where water bears live.
• 2. What does 'dormant' mean in paragraph 3? Which clue helps you?
• 3. Why do you think drying out helps a water bear survive?
• 4. The author says water bears are 'not invincible.' Use paragraph 5 to explain what invincible means.
• 5. Copy the sentence that gives evidence that water bears can survive in space.
• 6. What is the main idea of the whole passage?
• 7. Find a word in the passage that was new or tricky for you. What do you think it means? Which words around it helped you?
• 8. Write a question you would ask the author.