Let’s Go Bats — IELTS Reading Answers

examples of wildlife other than bats which do not rely on vision to navigate by

“Obviously the night-flying insects that they prey on must find their way about somehow. Deep-sea fish and whales have little or no light by day or by night. Fish and dolphins that live in extremely muddy water cannot see because, although there is light, it is obstructed and scattered by the dirt in the water”

Paragraph B gives deep-sea fish, whales and dolphins in muddy water as animals navigating without sight — wildlife other than bats.

how early mammals avoided dying out

“In the time when the dinosaurs dominated the daytime economy, our mammalian ancestors probably only managed to survive at all because they found ways of scraping a living at night”

Paragraph A explains mammalian ancestors 'managed to survive' by scraping a living at night, i.e. how they avoided dying out.

why bats hunt in the dark

“But the daytime economy is already heavily exploited by other creatures such as birds. Given that there is a living to be made at night, and given that alternative daytime trades are thoroughly occupied, natural selection has favoured bats that make a go of the night-hunting trade”

Paragraph A says daytime niches were 'thoroughly occupied', so natural selection favoured night hunting — the reason bats hunt in the dark.

how a particular discovery has helped our understanding of bats

“But the underlying mathematical theories of radar and sonar are very similar; and much of our scientific understanding of the details of what bats are doing has come from applying radar theory to them”

Paragraph E credits radar theory with much of our understanding of what bats do, which is the discovery that advanced bat research.

early military uses of echolocation

“After this technique had been invented, it was only a matter of time before weapons designers adapted it for the detection of submarines. Both sides in the Second World War relied heavily on these devices, under such codenames as Asdic (British) and Sonar (American), as well as Radar (American) or RDF (British),”

Paragraph D describes Second World War submarine detection using Asdic, Sonar and Radar — early military applications of echolocation.

“Experiments showed that, in fact, facial vision is nothing to do with touch or the front of the face, although the sensation may be referred to the front of the face, like the referred pain in a phantom limb”

The comparison is with 'referred pain in a phantom limb', so the adjective needed before 'limb' is 'phantom'.

“Blind people, without even being aware of the fact, are actually using echoes of their own footsteps and of other sounds, to sense the presence of obstacles”

Blind people sense obstacles by 'using echoes of their own footsteps', so the gap needs the reflected sounds, 'echoes'.

“Before this was discovered, engineers had already built instruments to exploit the principle, for example to measure the depth of the sea under a ship”

The instrument's purpose was 'to measure the depth of the sea', so the noun after 'measure the' is 'depth'.

“After this technique had been invented, it was only a matter of time before weapons designers adapted it for the detection of submarines”

Weapons designers adapted the technique for 'the detection of submarines', the noun filling the gap after 'detection of'.

“natural selection working on bats, had perfected the system tens of millions of years earlier”

The sentence needs the agent that perfected echolocation: 'natural selection working on bats, had perfected the system tens of millions of years earlier'.

“It is technically incorrect to talk about bat 'radar', since they do not use radio waves”

Bat 'radar' is technically wrong because bats 'do not use radio waves'; the gap needs that two-word term.

“But the underlying mathematical theories of radar and sonar are very similar; and much of our scientific understanding of the details of what bats are doing has come from applying radar theory to them”

What radar and sonar share is their 'underlying mathematical theories', the plural noun phrase the sentence requires.

“The American zoologist Donald Griffin, who was largely responsible for the discovery of sonar in bats, coined the term 'echolocation' to cover both sonar and radar, whether used by animals or by human instruments”

Griffin is introduced as 'The American zoologist', so the gap before his name needs that profession.