Hammer-headed Bat: a two-minute wildlife lesson

Creatures of the Night · day 2 of 7

Five facts

1. This is mainland Africa's biggest bat, with wings nearly 1 m across. Males and females look very different, and males can be almost twice as heavy.
2. A male's voice box is about three times the size of a female's. It is so big that it pushes his heart and lungs out of the way.
3. In the breeding season, males hang along rivers, each on a patch about 10 m wide, honking 60 to 120 times a minute and flapping their wings.
4. It mostly eats figs. It chews the fruit, swallows the juice and soft pulp, then spits out the rest, and the seeds it drops help plant new trees.
5. By day it hangs 20 to 30 m up in the treetops, sleeping with its wings over its nose. After 5 to 9 days it moves to a new tree.

The quiz

1. How do male hammer-headed bats compare with females?

• They are smaller and paler
• They can be almost twice as heavy (correct)
• They look exactly the same
• They have no fur on their heads

Males can weigh nearly double what females do, and the two look very different.

2. What is unusual about the male's voice box?

• It is so big it pushes the heart and lungs aside (correct)
• It is missing completely
• It sits on top of his head
• It only works in daylight

It is about three times the size of a female's and displaces other organs.

3. What do males do along rivers in the breeding season?

• Build nests of leaves
• Catch fish for the females
• Honk loudly and flap their wings (correct)
• Sleep in large silent groups

Each male hangs from a branch, honking again and again and flapping his wings.

4. How does the hammer-headed bat help forests?

• It eats the leaves of weeds
• It digs holes for rainwater
• It chases away harmful birds
• It spreads seeds from the fruit it eats (correct)

Its droppings contain seeds, so it may be an important seed spreader.

5. How does it usually sleep during the day?

• In a burrow under the ground
• Hanging high in a tree with its wings over its nose (correct)
• Floating on a river
• In a large crowd inside a cave

It roosts 20 to 30 m up in trees and covers its nose with its wings.

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