Big Brown Bat: a two-minute wildlife lesson

Creatures of the Night · day 1 of 7

Five facts

1. In one 1995 study, a colony of 150 of these bats in Indiana or Illinois ate about 600,000 cucumber beetles in a year, a serious crop pest.
2. It hunts in the dark by sound. From the echoes of its calls it can tell how far away something is, its size and shape, and which way it is moving.
3. A newborn pup is blind and weighs just 3 g. It can put on up to 0.5 g a day and starts flying at three to five weeks old.
4. In winter it hibernates, often in warm buildings. A store of special brown fat acts like a heater, warming its body fast when it wakes up.
5. White-nose syndrome, a fungal disease, has hit many North American bats hard. This one copes well, and in parts of the eastern US its numbers grew.

The quiz

1. Which crop pest did a colony of 150 big brown bats eat about 600,000 of in a year?

• Locusts
• Cucumber beetles (correct)
• Aphids
• Caterpillars

The 1995 study counted 600,000 cucumber beetles a year for one colony.

2. What can the big brown bat work out from the echoes of its calls?

• The colour of an insect
• The temperature of the air
• How far away an object is and which way it moves (correct)
• Whether rain is coming

Echoes tell it distance, size, shape and the direction an object is moving.

3. How much does a big brown bat pup weigh at birth?

• 3 g (correct)
• 30 g
• 60 g
• 100 g

Pups are born blind and weigh only 3 g.

4. What helps a big brown bat warm up quickly when it wakes from hibernation?

• Huddling inside a bird's nest
• Shivering its wings in the sun
• Eating a big meal first
• Stores of brown fat (correct)

Its large brown fat stores give energy to raise its body temperature fast.

5. How has the big brown bat fared against white-nose syndrome?

• It resists it well, and some populations have grown (correct)
• It has vanished from the eastern US
• It lost almost all its numbers
• It has never come into contact with it

It is fairly resistant, and some eastern US regions have seen its numbers rise.

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