# Do animals dream?: answers and explanations

Cambridge IELTS 21, Test 2, Reading Passage 1

Source: Passage, questions and answer key from Cambridge IELTS 21, Test 2, Reading Passage 1. © Cambridge University Press & Assessment. Used for educational practice. Explanations and evidence notes are written by Testmigo.

## Answer key

| Q | Answer | Proof |
| --- | --- | --- |
| 1 | rats | They found the patterns were very similar and concluded that the sleeping rats were dreaming about going through the maze. |
| 2 | visual | REM sleep activity was high in brain regions involved in processing visual information |
| 3 | half | but only half of it |
| 4 | temperature | It's thought that they don't experience REM sleep because during REM sleep animals are more vulnerable to extremes of temperature. |
| 5 | vivid | which are less vivid. |
| 6 | TRUE | when events are replayed in dreams, this helps to integrate memories into longer-term storage |
| 7 | FALSE | the truth is that we don't know if there is an internal experience of chasing rabbits |
| 8 | NOT GIVEN | while making a documentary, David Scheel of Alaska Pacific University in the USA housed an octopus |
| 9 | FALSE | squirted ink as though he were being attacked by a predator |
| 10 | TRUE | is only based on one animal ... brain imaging is needed to show that the octopuses are replaying sequences of activities |
| 11 | FALSE | we will never be able to experience any animal's dreams ... That goes for other humans' dreams too. |
| 12 | NOT GIVEN | Dogs primarily navigate the world using smell while spiders rely much more on vibrations |
| 13 | NOT GIVEN | it is possible that better understanding of these purposes might shed light on the true purpose of our own dreams |

## Why these answers are right

**1. rats.** Paragraph B describes researchers comparing the brain patterns of rats running a maze while awake with their patterns in REM sleep, finding them very similar and concluding the rats were dreaming. The row is about this animal, so the answer is rats.

**2. visual.** Paragraph C reports that sleeping pigeons showed high REM activity in brain regions that process visual information. The table says parts of the brain that deal with ___ input, and input paraphrases information, so the adjective needed is visual.

**3. half.** Paragraph D says whales and dolphins do not shut down their entire brain when they sleep, but only half of it, keeping the rest awake. The table's still have ___ their brain awake therefore needs the single word half.

The why and the trap for questions 4 onwards are free with an account on the [answers page](https://testmigo.com/ielts/reading/do-animals-dream/answers).

[Practice Do animals dream?](https://testmigo.com/ielts/reading/do-animals-dream)