| A | Walk into a pitch-black cave and your eyes are of little use. Shapes dissolve into shadows, and sounds echo unpredictably off the walls. Humans rely heavily on vision, so such an environment can be disorienting. Yet many animals, especially bats, navigate such darkness with remarkable ease. Their secret lies in a sensory skill called echolocation, the ability to interpret echoes from self-produced sounds. Although some birds and even a few mammals use it, echolocation is most famously associated with bats, whose lives depend on it in low-light environments. |
| B | Echolocation comes in two main forms. All animals produce some sounds naturally, but certain species have passive echolocation, meaning they only detect and interpret environmental noises, without creating specific calls for navigation. This allows them to hear and decode sound patterns made by others, such as the footsteps or wingbeats of nearby creatures. |
| C | Other animals possess active echolocation, in which they emit purposeful sound pulses, often ultrasonic, and read the returning echoes to form an acoustic "map" of their surroundings. This skill is vital for hunting and avoiding obstacles. By interpreting how quickly and strongly their sound waves bounce back, these animals can distinguish between prey, predators, and stationary objects. Active echolocation usually works within a short range, often just enough for a bat to swoop toward a moth or veer away from a cave wall at the last second. |
| D | One remarkable use of active echolocation is known as the Call Interference Avoidance mechanism. Some bat species emit calls at similar frequencies. When two individuals with overlapping signals meet in the same airspace, they adjust their call frequency to reduce overlap. This prevents their "sound pictures" from becoming scrambled, much like two radio stations shifting slightly on the dial to avoid static. |
| E | Echolocation also plays a role in bat self-defence. In certain caves, young bat pups cling to the roost ceiling while their mothers hunt. If a pup detects the approach of an owl, a common predator, its calls become nearly silent. This "sound freeze" makes it less detectable, as the owl relies heavily on acoustic cues to find its prey. Pups don't react to every noise, only to the wingbeat signatures and approach patterns that match likely threats. |
| F | Many people fear bats, often imagining them getting tangled in hair or spreading disease. While such fears are mostly exaggerated, bats are undeniably efficient hunters. They often detect prey, such as night-flying insects, first by sound or scent, and then refine their approach using echolocation. This sense is so precise that a bat can pluck a moving beetle from mid-air in complete darkness. |
| G | When humans encounter bats, most close passes are accidental. Bats cannot judge by sound alone whether a moving object is edible, so they sometimes "test" by approaching closely. If the target is unappealing, they veer away almost instantly. However, some bats, once they detect the specific wingbeat pattern of a preferred insect, will circle back repeatedly. Scientists are now investigating sound-based deterrents that might disrupt bat hunting patterns around crop fields, reducing agricultural losses without harming the animals. |
| H | Despite decades of study, much remains unknown about how echolocation is processed in the brain. Observations tell us it shapes hunting, defence, and communication, but the exact neural coding remains mysterious. Researchers are also exploring whether bats use echolocation for navigation across long distances. One theory suggests they may detect subtle changes in atmospheric pressure and environmental echoes over kilometres, helping them migrate or return to precise roosting sites year after year. |
Reading Passage 1 has eight paragraphs, A–H.
Which paragraph contains the following information?
Write the correct letter, A–H, in boxes 1–6 on your answer sheet.
| 1. how echolocation can assist in reproduction or social behaviour | |
| 2. a possible application of echolocation research for human benefit | |
| 3. the name for the ability to detect but not emit navigational calls | |
| 4. why only certain animals have evolved to use echolocation | |
| 5. how echolocation may help with long-distance movement | |
| 6. a description of how some animals avoid interfering with each other's sound signals |
Choose NO MORE THAN TWO WORDS from the passage for each answer.
Write your answers in boxes 7–9 on your answer sheet.
| • Owl's 7 alert the young bat to its presence |
| • Pup stays attached to 8 while mother hunts |
| • Pup stops making 9 when predator is nearby |
Complete the summary below.
Choose NO MORE THAN THREE WORDS from the passage for each answer.
Write your answers in boxes 10–13 on your answer sheet.
| Bat Hunting | |
| A bat is a highly skilled predator. It may first use its | 10 |
| to detect prey. As it closes in, it switches to | 11 |
| for accurate targeting. Humans are generally avoided because they are | 12 |
| However, once a bat identifies the distinct | 13 |
| of a preferred insect, it may return repeatedly to feed. | |
Questions 1–6
Questions 7–9
Questions 10–13
Tip: Complete each section under timed conditions (20 minutes per passage) before checking answers.
For practice purposes only
