Bats

Question 1

Describe the calls of bats found in an open habitat.

Answer 1

Mainly Constant frequency calls
Lower frequency
Longer calls
= projection over longer distances

Question 2

Describe the calls of bats found In a closed habitat.

Answer 2

Mainly Frequency modulated calls
Higher Frequency
Shorter calls
= detection of local objects

Question 3

Describe the calls of aerial hawking bats ?

Answer 3

Very loud calls

Insects are widely dispersed so require large detection range

Question 4

What is the prey of aerial hawking bats ?

Answer 4

Flying insects

Question 5

What behavioural characteristic do all bats use ?

Answer 5

Use scooping motion of the tail membrane to capture prey and prevent its escape.

Question 6

How do Aerial hawking bats use Biosonar ?

Answer 6

For food detection and orientation.

Question 7

Describe the ears of aerial hawking bats.

Answer 7

Small, are fast fliers so need to be streamlined.

Question 8

How do passive gleaners locate prey ?

Answer 8

Via walking noises or communication signals between insects

Question 9

Describe the calls of the passive gleaners,

Answer 9

Weak- only used for orientation

Do not want to mask prey.

Question 10

What is the prey of passive gleaning bats ?

Answer 10

Insects, arachnids, scorpions, vertebrates, frogs.

Question 11

Describe the ears of passive gleaning bats.

Answer 11

Large ears- to locate prey source.

Question 12

Describe how active gleaners locate prey

Answer 12

Locate motionless & silent prey using echolocation.

Question 13

What is highly specialised about active gleaners ?

Answer 13

Amazing echolocation resolution.

Question 14

Describe the calls of active gleaners.

Answer 14

Weak or loud calls to detect prey and orientate.

Become fainter as approach prey

Question 15

What type of diets do active gleaners have ?

Answer 15

Can be insectivores, carnivores, frugivores, nectarvores.

Question 16

Describe the beam emitted by oral emitters.

Answer 16

Broad beam

Question 17

Describe the beam emitted by nasal emitters

Answer 17

Narrow beams

Question 18

What type of emitter are the majority of bat species ?

Answer 18

Nasal emitters

Question 19

What is the advantage of being a nasal beam emitter ?

Answer 19

Can chew prey item at same time as echolocating

Question 20

What is the role of the nostrils in beam formation ?

Answer 20

The 2 nostrils narrow the sound beam to give directionality of the beam.

Question 21

Why do bats reduce their inter call intervals when approaching a target ?

Answer 21

They only produce next call when the echo of interest has been heard.
Therefore can reduce time between calls on approach as echo occurs quicker

Question 22

What indicates the distance/range of the target ?

Answer 22

The delay between the sound emission and reception.

Question 23

Give the formula for range (distance).

Answer 23

Delay * C/2 (m)

C- speed of sound

Question 24

What Is the resolution of bat calls ?

Answer 24

How well they can detect an organism.

Between 5mm and 0.3 mm

Question 25

What are the issues with the signal overlap zone ?

Answer 25

Reduces the ability to detect an echo.

Question 26

Why do bats reduce call duration when approaching a target ?

Answer 26

Shortens the Signal overlap zone. Enabling accurate detection of close range prey.

Question 27

What is echo call overlap ?

Answer 27

If the prey item is too close to the echolocating bat.
‘In signal overlap zone’
The echo will return before the call is finished, creating overlap

Question 28

Give the formula for calculating the signal overlap zone.

Answer 28

Call duration * Ca/2 (m)

C- Speed of sound in air

Question 29

Bat calls can be very loud.

True or false ?

Answer 29

True, up to 133 dB

permanent damage- 140 dB

Question 30

What are the problems with these loud bat calls ?

Answer 30

Bats could deafen themselves by their own calls.

Question 31

How do bats prevent deafness ?

Answer 31

Create temporary deafness, by muscle contraction
Protection up to 200 Hz.
(most rapidly working muscle)