The Wings of Bats

SCIENCE CONCEPT:

A bat's wing consists of bones that are very similar to the bones in a human arm and hand. Long arm bones, with extra-long extended finger bones, are covered with a double layer of thin skin called a membrane. The second and third fingers, along with the membrane in between, give the wing a stiff leading edge similar to an airplane's, while the third finger forms the wing tip.

STUDENT OBJECTIVE:

The student will draw the wing of a bat, a bird wing, and the arm of a human to show the similarities and differences between the three of them.

OVERVIEW:

As the student draws the wing of a bat, the wing of a bird, and a human arm they will observe the similarities in the three. The student will also ascertain the differences between the three of them and what makes each unique. Both bats and birds have mastered flight with their wings.

PREPARATION TIME:

15-20 minutes.

LESSON TIME:

25 minutes.

TEACHER PREP:

Gather pictures of a bat's wing, a bird's wing, and the arm of a human showing the bone structure of all three, along with their outlined form.

WORDS TO KNOW:

chiroptera

handwing

membrane

muscle fibers

clawed thumbs

webbed hands

TEACHER TEXT:

The name given to bats is the animal order: "chiroptera" is Greek for handwing. Long arm bones, with extra-long extended finger bones, are covered with a double layer of thin skin called a membrane. The membrane is so thin that you can see light through it. It is made up of fine blood vessels, elastic fibers and muscle fibers. The fibers help keep the flight membrane taut and aid in folding of the wing membrane when the bat is at rest.

The membrane stretches over the arm bones and extended finger bones to the sides of the body and leg forming an airfoil surface. In some bats, this flight membrane may also extend between the legs and include the tail. The small clawed thumbs (often used for climbing) are left free. The second and third fingers, along with the membrane in between, give the wing a stiff leading edge similar to an airplane's, while the third finger forms the wing tip.

A bat's wings act like webbed hands. The bat can move its wings like we move our fingers enabling it to change its wings' shape rapidly to dart, flip, and turn quickly. Although birds use their tails to brake and steer, bats use their wings by folding one wing for a second and using one independently of the other. Many bats have also mastered hovering flight, similar to hummingbirds and helicopters, that enables them to remain stationery in flight, while other bats are able to achieve brief periods of gliding flight.

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Last modified: Sat Aug 23 14:04:12 PDT 1997