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.
- An animal that has no backbone. Worms, clams, insects, and lobsters are all invertebrates.
- Someone who plots a course for a journey.
- To move about secretly and quietly as if looking for prey.
- Humans cannot feel the Earth's magnetic field. What tool do people use to read the Earth's magnetic field?
[anno: People use a compass to read the Earth's magnetic field.]
- What are some other ways that people navigate? What are the tools that people use to navigate? How do these devices work? Name two other ways that people navigate. Write about the tool that people might use to navigate this way.
[anno: Answers will vary but could include that people use the Sun, the Moon, and the stars to navigate. The tool that people use to navigate with the Sun, the Moon, and the stars could include a sextant, a star map, or a telescope. Another way that people navigate is by using a GPS or Global Positioning Device.]