TF阅读真题第859篇Food Caching by Scrub Jays

Food Caching by Scrub Jays

 

 

The western scrub jay is a highly intelligent bird, and biologists have conducted a number of experiments on its cognitive abilities based on its propensity to cache (hide) food such as acorns, seeds, or worms for later consumption. Since they do not migrate for the winter, scrub jays must prepare in advance, storing food in caches (hiding places)to get through the cold months when less food is naturally available. In addition to this predictable seasonal change, however, scrub jays have to contend with two other factors that require their knowledge of the world to be updated more rapidly: first, different kinds of food tend to perish (spoil and become uneatable) at different rates; and, second, other scrub jays may find and eat their cache (hidden food) before they do.

In a series of complex and very clever experiments, scrub jays have been shown to remember what kind of food they have hidden where, and, more impressively, when they did so. When given the option of recovering either previously cached wax worms(their favorite food, but one that perishes rapidly) or peanuts(which are less preferred, but last longer), scrub jays would attempt to recover the wax worms if the delay between caching and recovery was short(4 hours)but would recover peanuts when the delay was long(120 hours). Wax worms are still tasty after 4 hours, so it makes sense to go for them after a short delay, but after 120 hours they have gone bad and become inedible (uneatable) and there is no point in recovering them. It seems, then, that the scrub jays have some means of keeping track of what they have cached, where they did so, and also when they did so, with the result that they do not waste effort recovering bad food, or, conversely, they do not spend time and effort recovering less preferred nonperishable foods, like peanuts, when there are more exciting and tasty foods like wax worms to be had.

In addition to recovering their own caches, scrub jays are also very adept at pilfering (stealing) the stores of other scrub jays. To counter such pilfering, jays frequently recache their food if there are competitor birds around that have had the opportunity to observe where food has been stored. In another series of experiments, scrub jays were able to keep track of which food caches had been seen by competitor birds, and even to remember exactly which specific individual had seen them hide their cache. In one experiment, for example, the birds were given access to food and allowed to cache in private or in the presence of an observer bird. After a three-hour delay, the birds were then allowed to recover their caches, and to recache the food in a new tray if they chose to do so. Jays were much more likely to recover their caches and hide them in the new tray if they had been observed initially than if they had cached in private. This suggests they were sensitive to the social context in which they had originally cached: food was moved to a new spot only if there was a risk that it could be pilfered by another bird.

Scrub jays also engage in various kinds of cache-protection strategies at the time of caching: if they can be seen by another bird as they cache, scrub jays are much more likely to choose caching sites in shady areas, or those that are less well lit(presumably because this makes it harder for a competitor to see exactly where they are caching), and they will also choose a more distant site over a closer one. Further, they are more likely to move a food item around multiple times between different cache sites before finally settling on one, making it difficult for a competitor to keep track of exactly where a food item ends up. Most intriguingly of all, it appears that these recaching tactics are dependent on a scrub jay’s previous experience of pilfering: the only birds to recache their food after being observed are those that have previously taken food from other birds’ caches. Birds with no experience of raiding another bird’s cache sites show no tendency to recache their own food if another bird is witness to their caching.

 

 

 

 

 

1

The western scrub jay is a highly intelligent bird, and biologists have conducted a number of experiments on its cognitive abilities based on its propensity to cache (hide) food such as acorns, seeds, or worms for later consumption. Since they do not migrate for the winter, scrub jays must prepare in advance, storing food in caches (hiding places)to get through the cold months when less food is naturally available. In addition to this predictable seasonal change, however, scrub jays have to contend with two other factors that require their knowledge of the world to be updated more rapidly: first, different kinds of food tend to perish (spoil and become uneatable) at different rates; and, second, other scrub jays may find and eat their cache (hidden food) before they do.

According to paragraph 1, scrub jays hide food for later consumption because they

Factual Information Questions事实信息题

Aare highly intelligent

Bremain in their habitats during the cold months of winter

Cneed to have food ready for immediate consumption at all times

Dneed to eat their food while out of the sight of other scrub jays

 

2

The western scrub jay is a highly intelligent bird, and biologists have conducted a number of experiments on its cognitive abilities based on its propensity to cache (hide) food such as acorns, seeds, or worms for later consumption. Since they do not migrate for the winter, scrub jays must prepare in advance, storing food in caches (hiding places)to get through the cold months when less food is naturally available. In addition to this predictable seasonal change, however, scrub jays have to contend with two other factors that require their knowledge of the world to be updated more rapidly: first, different kinds of food tend to perish (spoil and become uneatable) at different rates; and, second, other scrub jays may find and eat their cache (hidden food) before they do.

Paragraph 1 suggests that scrub jays know which of the following about the various foods they eat?

Inference Questions推理题

AWhich foods are easier to store

BWhere each food can be gathered most quickly

CHow quickly each type of food spoils

DWhich foods provide more energy

 

3

In a series of complex and very clever experiments, scrub jays have been shown to remember what kind of food they have hidden where, and, more impressively, when they did so. When given the option of recovering either previously cached wax worms(their favorite food, but one that perishes rapidly) or peanuts(which are less preferred, but last longer), scrub jays would attempt to recover the wax worms if the delay between caching and recovery was short(4 hours)but would recover peanuts when the delay was long(120 hours). Wax worms are still tasty after 4 hours, so it makes sense to go for them after a short delay, but after 120 hours they have gone bad and become inedible (uneatable) and there is no point in recovering them. It seems, then, that the scrub jays have some means of keeping track of what they have cached, where they did so, and also when they did so, with the result that they do not waste effort recovering bad food, or, conversely, they do not spend time and effort recovering less preferred nonperishable foods, like peanuts, when there are more exciting and tasty foods like wax worms to be had.

Why does the author state that wax worms “are still tasty after 4 hours, so it makes sense to go for them after a short delay, but after 120 hours they have gone bad and become inedible (uneatable) and there is no point in recovering them”?

Rhetorical Purpose Questions修辞目的题

ATo provide an explanation for the behavior of scrub jays in the experiments

BTo confirm the preference of scrub jays for wax worms over peanuts

CTo explain why cached wax worms become inedible after a short delay

DTo illustrate how scrub jays spend time and effort in recovering cached food

 

4

In addition to recovering their own caches, scrub jays are also very adept at pilfering (stealing) the stores of other scrub jays. To counter such pilfering, jays frequently recache their food if there are competitor birds around that have had the opportunity to observe where food has been stored. In another series of experiments, scrub jays were able to keep track of which food caches had been seen by competitor birds, and even to remember exactly which specific individual had seen them hide their cache. In one experiment, for example, the birds were given access to food and allowed to cache in private or in the presence of an observer bird. After a three-hour delay, the birds were then allowed to recover their caches, and to recache the food in a new tray if they chose to do so. Jays were much more likely to recover their caches and hide them in the new tray if they had been observed initially than if they had cached in private. This suggests they were sensitive to the social context in which they had originally cached: food was moved to a new spot only if there was a risk that it could be pilfered by another bird.

The word “counter” in the passage is closest in meaning to

Vocabulary Questions词汇题

AReduce

Bact against

Ccomplicate

DDelay

 

5

In addition to recovering their own caches, scrub jays are also very adept at pilfering (stealing) the stores of other scrub jays. To counter such pilfering, jays frequently recache their food if there are competitor birds around that have had the opportunity to observe where food has been stored. In another series of experiments, scrub jays were able to keep track of which food caches had been seen by competitor birds, and even to remember exactly which specific individual had seen them hide their cache. In one experiment, for example, the birds were given access to food and allowed to cache in private or in the presence of an observer bird. After a three-hour delay, the birds were then allowed to recover their caches, and to recache the food in a new tray if they chose to do so. Jays were much more likely to recover their caches and hide them in the new tray if they had been observed initially than if they had cached in private. This suggests they were sensitive to the social context in which they had originally cached: food was moved to a new spot only if there was a risk that it could be pilfered by another bird.

According to paragraph 3, all of the following are true about pilfering by scrub jays EXCEPT:

Negative Factual Information Questions否定事实信息题

AScrub jays are able to recover caches that have been pilfered by other scrub jays.

BScrub jays take steps to ensure that their caches are not pilfered.

CScrub jays often pilfer the caches of other scrub jays.

DScrub jays know when their caches are likely to be pilfered.

 

6

In addition to recovering their own caches, scrub jays are also very adept at pilfering (stealing) the stores of other scrub jays. To counter such pilfering, jays frequently recache their food if there are competitor birds around that have had the opportunity to observe where food has been stored. In another series of experiments, scrub jays were able to keep track of which food caches had been seen by competitor birds, and even to remember exactly which specific individual had seen them hide their cache. In one experiment, for example, the birds were given access to food and allowed to cache in private or in the presence of an observer bird. After a three-hour delay, the birds were then allowed to recover their caches, and to recache the food in a new tray if they chose to do so. Jays were much more likely to recover their caches and hide them in the new tray if they had been observed initially than if they had cached in private. This suggests they were sensitive to the social context in which they had originally cached: food was moved to a new spot only if there was a risk that it could be pilfered by another bird.

According to paragraph 3, if a jay knows it has been observed storing food, it will

Factual Information Questions事实信息题

Areturn to the cache frequently to ensure that it is safe

Beat the food immediately

Cstay by the cache until it is sure the observer will not return

Dmove the food to a different hiding place

 

7

Scrub jays also engage in various kinds of cache-protection strategies at the time of caching: if they can be seen by another bird as they cache, scrub jays are much more likely to choose caching sites in shady areas, or those that are less well lit(presumably because this makes it harder for a competitor to see exactly where they are caching), and they will also choose a more distant site over a closer one. Further, they are more likely to move a food item around multiple times between different cache sites before finally settling on one, making it difficult for a competitor to keep track of exactly where a food item ends up. Most intriguingly of all, it appears that these recaching tactics are dependent on a scrub jay’s previous experience of pilfering: the only birds to recache their food after being observed are those that have previously taken food from other birds’ caches. Birds with no experience of raiding another bird’s cache sites show no tendency to recache their own food if another bird is witness to their caching.

The word “presumably” in the passage is closest in meaning to

Vocabulary Questions词汇题

AProbably

BMostly

CUsually

DEspecially

 

8

Scrub jays also engage in various kinds of cache-protection strategies at the time of caching: if they can be seen by another bird as they cache, scrub jays are much more likely to choose caching sites in shady areas, or those that are less well lit(presumably because this makes it harder for a competitor to see exactly where they are caching), and they will also choose a more distant site over a closer one. Further, they are more likely to move a food item around multiple times between different cache sites before finally settling on one, making it difficult for a competitor to keep track of exactly where a food item ends up. Most intriguingly of all, it appears that these recaching tactics are dependent on a scrub jay’s previous experience of pilfering: the only birds to recache their food after being observed are those that have previously taken food from other birds’ caches. Birds with no experience of raiding another bird’s cache sites show no tendency to recache their own food if another bird is witness to their caching.

According to paragraph 4. which of the following is true about a scrub jay that has never taken food from another bird’s cache?

Factual Information Questions事实信息题

AIt is not likely to use recaching tactics.

BIt is not likely to find enough food to eat.

CIt is likely to be allowed to witness another bird caching.

DIt is likely to have difficulty keeping track of its own cache.

9

In a series of complex and very clever experiments, scrub jays have been shown to remember what kind of food they have hidden where, and, more impressively, when they did so. [■]When given the option of recovering either previously cached wax worms(their favorite food, but one that perishes rapidly) or peanuts(which are less preferred, but last longer), scrub jays would attempt to recover the wax worms if the delay between caching and recovery was short(4 hours)but would recover peanuts when the delay was long(120 hours). [■]Wax worms are still tasty after 4 hours, so it makes sense to go for them after a short delay, but after 120 hours they have gone bad and become inedible (uneatable) and there is no point in recovering them. [■]It seems, then, that the scrub jays have some means of keeping track of what they have cached, where they did so, and also when they did so, with the result that they do not waste effort recovering bad food, or, conversely, they do not spend time and effort recovering less preferred nonperishable foods, like peanuts, when there are more exciting and tasty foods like wax worms to be had.[■]

Look at the four squaresthat indicate where the following sentence could be added to the passage

 

There is an intelligent reason for these choices.

Insert Text Questions句子插入题

Where would the sentence best fit？Click on a square  sentence to the passage.

 

10

The food-caching behavior of scrub jays reveals that these birds have impressive cognitive abilities.

Prose Summary Questions概要小结题

Select 3 answers

AScrub jays rapidly update their knowledge of the world just before winter to determine which foods they have to eat immediately and which to store to get through the cold months.

BExperiments show that if another bird is present while a scrub jay caches food, the jay will remember which bird it was and which cache was being hidden.

CScrub jays protect their food by storing it in a small number of large caches, so that it is easier to defend and the locations are easier to recall.

DScrub jays remember important details about food they have cached, which allows them to spend their time recovering edible foods rather than food that has gone bad.

EScrub jays recognize when a cache belongs to another jay and are careful not to take from competitors, especially when the bird who owns the cache is present.

FA scrub jay’s tendency to move its cache when it has been observed seems to depend upon whether the jay has itself ever pilfered another bird’s cache.