Long-eared bat
Bats are not always the most popular of creatures in our gardens, because many people regard them with suspicion, but they are amongst the most exceptional.
All British bats have an echo-location system which enables them to ‘see’ in the dark. Most species make sounds through their mouths which bounce back off anything around them; that is how they detect prey and avoid flying into things!
Bats will eat any insects that fly by night so moths are obviously high on the menu. However some types of moth have developed a good sense of hearing and can take evasive action when they hear the echo-location sounds of a bat.
To overcome this problem the brown long-eared bat has developed a very quiet echo-location system which is inaudible to moths, in fact it is often referred to as the 'whispering bat'. The sounds that it makes are so quiet that it has had to evolve ridiculously large ears to be able to hear its own sounds.
Look carefully at the ears of the brown long-eared bat and you will see that they act like a parabolic reflector, they even have a flap of skin to bounce sound back into their ears; this is known as a tragus.
When the brown long-eared bat goes to sleep it tucks its ears underneath its arms and only the tragus remains upstanding, in this state it can look like a bat with very small ears.