Mass Strandings Of Whales And Dolphins - IELTS Listening Answers & Explanations
From Cambridge IELTS 09 Academic Listening Test 1 · Part 4 · Questions 31–40
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Questions
Questions 31–40 Note Completion
Complete the notes below.
Write NO MORE THAN TWO WORDS for each answer.
Mass Strandings of Whales and Dolphins
Mass strandings: situations where groups of whales, dolphins, etc. swim onto the beach and die
Common in areas where the 31 can change quickly
Several other theories:
Parasites
e.g. some parasites can affect marine animals’ 32, which they depend on for navigation
Toxins
Poisons from 33 or animals are commonly consumed by whales
e.g. Cape Cod (1988) – whales were killed by saxitoxin
Accidental Strandings
Animals may follow prey ashore, e.g. Thurston (1995)
Unlikely because the majority of animals were not 34 when they stranded
Human Activity
35 from military tests are linked to some recent strandings
The Bahamas (2000) stranding was unusual because the whales
- were all 36
- were not in a 37
Group Behaviour
- More strandings in the most 38 species of whales
- 1994 dolphin stranding – only the 39 was ill
Further Reading
Marine Mammals Ashore (Connor) – gives information about stranding 40
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q31 | tide / tides | Unfortunately, this type of event is a frequent occurrence in some of the locations that you’ll be travelling to, where sometimes the tide goes out suddenly, confusing the animals | Excerpt/Transcript Explanation: The transcript states that in certain places, the water level changes very fast, which makes it hard for whales and dolphins to know where to go. Answer Explanation: The answer is about the regular rise and fall of the ocean level. Reason For Correctness: The correct answer is 'tide/tides' because the transcript explains that mass strandings happen often in places where the water level moves away from the land very quickly. When the water 'goes out suddenly', it confuses the animals. The word 'suddenly' is a synonym for 'quickly' used in the notes. |
| Q32 | hearing / ear / ears | For instance, a type of worm is commonly found in the ears of dead whales. Since marine animals rely heavily on their hearing to navigate, this type of infestation has the potential to be very harmful | Excerpt/Transcript Explanation: The transcript explains that worms (parasites) are often found in the ears of whales. It notes that whales use their hearing to move around and find their way, so having parasites in their ears is very bad for them. Answer Explanation: The answer identifies the body part (ears) or the sense (hearing) that parasites affect, which interferes with how marine animals find their way. Reason For Correctness: The correct answer is supported by the transcript's explanation of the first theory regarding mass strandings. The speaker mentions that parasites, such as worms, are often found in the ears of dead whales. Because these animals depend on their hearing to navigate (follow a route or find where they are), these parasites can cause a lot of damage and lead to strandings. |
| Q33 | plants / fish / fishes | Many toxins, as I’m sure you’re aware, originate from plants, or animals | Excerpt/Transcript Explanation: The transcript states that many of the poisons that can hurt marine life come from plants or animals. Answer Explanation: The answer identifies the two things (plants and animals) that toxins or poisons come from before whales eat them. Reason For Correctness: The correct answer is 'plants' and 'animals' because the text explains that toxins found in marine creatures often come from these two sources. In the section about the 'toxins' theory, the speaker mentions that these poisons originate from plants or animals, which the whales then eat. The example following this mentions whales eating tuna (a fish) that contained a toxin. |
| Q34 | feeding | However, this idea does not seem to hold true for the majority of mass strandings because examination of the animals’ stomach contents reveal that most had not been feeding as they stranded | Excerpt/Transcript Explanation: The transcript says that scientists checked the stomachs of the stranded animals and found that the majority were not eating at the time, which means they probably weren't chasing food onto the shore. Answer Explanation: The answer 'feeding' refers to the action of animals eating their food. Reason For Correctness: The correct answer explains why the idea of 'Accidental Strandings' (animals following prey to the shore) is usually wrong. The speaker notes that researchers looked at the 'stomach contents' of the animals and found that the 'majority' (most) of them were 'not feeding' (not eating) when they got stuck on the beach. |
| Q35 | noise / noises | Noises such as those caused by military exercises are of particular concern and have been pinpointed as the cause of some strandings of late | Excerpt/Transcript Explanation: The transcript states that loud sounds made during military drills are a big problem and are the direct reason why some whales and dolphins have ended up on beaches lately. Answer Explanation: The answer "noise" or "noises" refers to loud sounds found in the ocean. Reason For Correctness: The correct answer is "noise/noises" because the speaker explains that human activities, like military tests, create loud sounds in the water. These sounds are a reason why whales and dolphins swim onto the land. The speaker uses the words "military exercises" to mean military tests and says the "noises" from them are "the cause" of recent shore strandings. |
| Q36 | healthy | For one, all the stranded animals were healthy | Excerpt/Transcript Explanation: The transcript says that one reason this event was different from previous ones is that every animal found on the shore was well and not sick. Answer Explanation: The answer 'healthy' means that the whales involved in the Bahamas stranding were well and did not have any diseases or sickness. Reason For Correctness: The correct answer is 'healthy' because the speaker explains why the stranding in the Bahamas in 2000 was different from others. Usually, stranded animals might be sick or weak, but in this specific case, all of the whales were in good physical health. This was one of the factors that led researchers to look for a different cause, such as human-made noise. |
| Q37 | group | In addition, the animals were spread out along 38 kilometres of coast, whereas it’s more common for the animals to be found in a group when mass strandings occur | Excerpt/Transcript Explanation: The transcript explains that normally, when many sea animals wash up on shore, they are found together in a group. But in the Bahamas case, they were scattered over a very long distance (38 kilometers) instead. Answer Explanation: The answer "group" refers to a collection of animals that are close together in the same location. Reason For Correctness: The correct answer is "group" because the transcript mentions that the Bahamas event in 2000 was "different from previous strandings." Usually, when many animals get stuck on a beach at the same time, they are found clustered together. However, in this specific case, they were found far apart from each other along a long stretch of land, meaning they were not in a single cluster or group. |
| Q38 | social | This is a particularly interesting theory since the whales that are thought to be most social – the toothed whales – are the group that strand the most frequently | Excerpt/Transcript Explanation: The transcript explains that the whales that are the most social are the ones that get stuck on the beach in large groups the most often. Answer Explanation: The answer "social" refers to whale species that live and travel together in groups. Reason For Correctness: The correct answer is social because the transcript links the frequency of mass strandings to the social nature of certain whales. It mentions a group known as 'toothed whales', which are considered the most 'social'—meaning they enjoy being part of a group—and notes that they are also the group that strands most often. This supports the 'group behavior' theory mentioned in the notes. |
| Q39 | leader | Examination of the dead animals revealed that apart from the leader, all the others had been healthy at the time of their death | Excerpt/Transcript Explanation: The transcript explains that when researchers looked at the dolphins that died in 1994, they found that only the lead animal was sick, while the rest were healthy. Answer Explanation: The answer 'leader' means the animal that is at the front or in charge of a group. Reason For Correctness: The correct answer describes a specific event in 1994 when a group of dolphins got stuck on the beach. Scientists checked the bodies and found that only the main dolphin (the leader) was sick. All the other dolphins were healthy, but they followed the sick leader onto land. This helps explain the theory that these social animals follow their head member even if that member is making a bad choice or is ill. |
| Q40 | network / networks | I recommend John Connor’s Marine Mammals Ashore as an excellent starting point if you’re interested in finding out more about these networks, or establishing one yourself | Excerpt/Transcript Explanation: The transcript suggests a specific book for anyone who wants to learn more about the groups (networks) that work on beaches to help stranded sea animals. Answer Explanation: The answer is networks, which means groups of people who work together to help whales and dolphins that are stuck on the beach. Reason For Correctness: The correct answer is networks because the speaker talks about 'stranding networks' as groups that rescue animals. Then, the speaker suggests reading John Connor’s book if you want to find more information about these 'networks'. |
Transcript
Good afternoon everyone. Well, with some of you about to go out on field work it’s timely that in this afternoon’s session I’ll be sharing some ideas about the reasons why groups of whales and dolphins sometimes swim ashore from the sea right onto the beach and, most often, die in what are known as ‘mass strandings’.
Unfortunately, this type of event is a frequent occurrence in some of the locations that you’ll be travelling to, where sometimes the tide goes out suddenly, confusing the animals. However, there are many other theories about the causes of mass strandings.
The first is that the behaviour is linked to parasites. It’s often found that stranded animals were infested with large numbers of parasites. For instance, a type of worm is commonly found in the ears of dead whales. Since marine animals rely heavily on their hearing to navigate, this type of infestation has the potential to be very harmful.
Another theory is related to toxins, or poisons. These have also been found to contribute to the death of many marine animals. Many toxins, as I’m sure you’re aware, originate from plants, or animals. The whale ingests these toxins in its normal feeding behaviour but whether these poisons directly or indirectly lead to stranding and death, seems to depend upon the toxin involved.
In 1988, for example, fourteen humpback whales examined after stranding along the beaches of Cape Cod were found to have been poisoned after eating tuna that contained saxitoxin, the same toxin that can be fatal in humans.
Alternatively, it has also been suggested that some animals strand accidentally by following their prey ashore in the confusion of the chase. In 1995 David Thurston monitored pilot whales that beached after following squid ashore. However, this idea does not seem to hold true for the majority of mass strandings because examination of the animals’ stomach contents reveal that most had not been feeding as they stranded.
There are also some new theories which link strandings to humans. A growing concern is that loud noises in the ocean cause strandings. Noises such as those caused by military exercises are of particular concern and have been pinpointed as the cause of some strandings of late.
One of these, a mass stranding of whales in 2000 in the Bahamas coincided closely with experiments using a new submarine detection system. There were several factors that made this stranding stand out as different from previous strandings. This led researchers to look for a new cause. For one, all the stranded animals were healthy. In addition, the animals were spread out along 38 kilometres of coast, whereas it’s more common for the animals to be found in a group when mass strandings occur.
A final theory is related to group behaviour, and suggests that sea mammals cannot distinguish between sick and healthy leaders and will follow sick leaders, even to an inevitable death. This is a particularly interesting theory since the whales that are thought to be most social – the toothed whales – are the group that strand the most frequently.
The theory is also supported by evidence from a dolphin stranding in 1994. Examination of the dead animals revealed that apart from the leader, all the others had been healthy at the time of their death.
Without one consistent theory however it is very hard for us to do anything about this phenomenon except to assist animals where and when we can. Stranding networks have been established around the world to aid in rescuing animals and collecting samples from those that could not be helped. I recommend John Connor’s Marine Mammals Ashore as an excellent starting point if you’re interested in finding out more about these networks, or establishing one yourself.