Lost? Not if You're a Lobster

Migrating birds are champion navigators. So are sea turtles. But the Caribbean spiny lobster, a humble invertebrate? Believe it.

Despite their primitive brains, spiny lobsters, like some birds and turtles, are now thought to have an ability known as true navigation. True navigators never get lost because they can always pinpoint exactly where they are on Earth, and which direction to walk, fly, or swim to get home.

Scientists first became curious when they noticed that, although spiny lobsters prowl for food at night when it's pitch black on the ocean floor, they easily find their way home again. To test the lobsters' sense of direction, researchers captured 100 spiny lobsters, then did their best to confuse them. The scientists covered the lobsters' eyes with rubber caps, hung their storage tanks from swinging ropes, and drove them on a boat around and around in circles. When the lobsters were released, seven to twenty miles away, they still found their way back home, no problem.

How do the lobsters do it? Scientists aren't exactly sure, but they think it has something to do with the Earth's magnetic field. Spiny lobsters contain bits of a mineral, magnetite, which is used in making compasses. This may help them read the Earth's magnetic map so they always go in the right direction.

Vocabulary

invertebrate:
An animal that has no backbone. Worms, clams, insects, and lobsters are all invertebrates.

navigator:
Someone who plots a course for a journey.

prowl:
To move about secretly and quietly as if looking for prey.

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Activity

  1. Why did scientists want to study how lobsters can navigate?
    [anno: Scientists wanted to figure out how lobsters can find their way home in the dark.]
  2. How do think lobsters navigate?
    [anno: Scientists think that lobsters use the Earth's magnetic field to navigate.]
  3. What substance is found in a lobster's body that might help the lobster to navigate?
    [anno: Lobsters have magnetite in their bodies.]
  4. What might it feel like to be a lobster navigating back home? How might the lobster use its senses? How might the forces acting upon the lobster feel? Write a few sentences to describe how a lobster might feel as it navigates?
    [anno: Answers will vary.]