雅思阅读 68: The Prairie Dog's Dictionary（草原犬鼠的词典）

改编参考 Slobodchikoff 研究 / MIT Press（经典综述改编）。雅思阅读 Section 3 难度，约 1050 词。 素材来源：https://furrycritter.com/pages/articles/small_mammals/prairie_dog_vocalizations.htm

Reading Passage

A. When a predator approaches a prairie-dog colony, the first animal to spot it does not flee immediately. It stands upright on a mound and begins to call — a sharp, repetitive "chee" that rings across the grassland. Within seconds, every animal nearby has dived for its burrow, or frozen, or stood to watch. For decades, biologists assumed this call was nothing more than an emotional alarm: a shrill cry meaning "danger", the equivalent of a human gasp. The assumption was convenient, because it placed such vocalisations firmly below the threshold of "language", a skill reserved for humans and, at best, a handful of primates and songbirds. Then, from the 1970s onward, a researcher named Con Slobodchikoff and his colleagues at Northern Arizona University began recording these calls and analysing them on a machine that broke each sound into its acoustic components. What they found challenged the neat boundary between animal "signals" and human "words". The prairie dog, it turned out, was saying considerably more than "danger". The work was painstaking: a single colony had to be observed for years, and the same call had to be recorded under many conditions before any pattern could be trusted.

B. The first clue was that the calls were not interchangeable. A call given when a hawk circled overhead was acoustically different from the call given when a coyote trotted past, and both differed again from the call for a domestic dog, a ferret, or simply a walking human. Spectrograms — the visual plots of sound — showed distinct patterns in pitch, duration and frequency for each predator type. Most remarkably, the colony's response to each call matched the threat. A hawk call sent every animal diving straight into the nearest burrow entrance, because a hawk attacks from above in a fast, straight swoop. A coyote call produced a different reaction: animals stood on their hind legs, scanned the ground, and moved toward the rims of their burrows, keeping the slowly approaching canid in sight. Listeners, in other words, did not merely hear "something is wrong". They extracted which predator it was, and acted accordingly. The calls functioned as labels for external objects — what linguists call referential signals. That a small mammal should label a predator by type challenged the assumption that such signalling required the large brain and social life of a primate.

C. But the most surprising discovery was still to come. Within a single predator category, the calls also varied to describe features of the individual animal approaching. In a famous series of experiments, the researchers led dogs of different colours and sizes — a black dog, a brown dog, a tall slender dog, a short stocky one — past the same colony on different days, always without the animals themselves being present at the same moment. The recorded calls differed not just by predator type but by the specific details: one call tended to accompany a large black shape, another a small brown one. The team argued that within the basic "dog" call, prairie dogs were encoding attributes such as size, colour and even shape, in the same way that a single human sentence can carry several pieces of information at once. If true, this was more than an alarm system; it approached the flexible, descriptive quality that had long been treated as the defining hallmark of human speech. The very economy of the call is striking: a single "chee", lasting less than a second, was being asked to carry a whole phrase of description.

D. Not everyone was persuaded, and the debate is instructive. Skeptics accept that the calls are predator-specific, but they dispute the stronger claim that they encode arbitrary attributes the way words do. They point out that prairie dogs have no grammar in any human sense: there is no evidence that the animals recombine call elements into new meanings the way humans arrange words into sentences. A fixed call for "hawk" that varies slightly by context is still, the argument goes, a closed, instinctive repertoire rather than an open, creative language. The animals also never seem to call about events that are not present — they do not gossip about yesterday's hawk or plan for tomorrow. Without displacement, the ability to refer to things remote in space and time, many linguists would still withhold the word "language". What remains beyond dispute is that the calls convey remarkably specific, context-sensitive information that listeners use to make life-or-death decisions. Whether that information amounts to "language" is, in the end, less important than the fact that it works: a colony of ground squirrels survives because one of them can describe a threat well enough for the others to respond correctly.

E. Why should this matter for humans? The study of prairie dogs sits inside a wider reassessment of where language comes from. For most of the twentieth century, the human capacity for symbolic communication was treated as a sudden, singular leap, unique to our species. The slow accumulation of evidence from prairie dogs, from the alarm calls of meerkats, from the songs of whales and the gestures of apes, tells a different story: the building blocks of symbolic reference — labelling objects, encoding their features, adapting the signal to the threat — may be ancient, widespread and far more common than once assumed. Human language, on this view, is not a wall that nature breached once, but a tower built on foundations that many animals already share. The prairie dog's "chee" will never discuss the weather or recall a distant summer, but it forces us to ask whether the line between an instinctive cry and a meaningful word is quite as bright as we liked to think. If even a ground squirrel can label the colour of an approaching threat, then the capacity for reference may be older, and more democratic, than the human story had long assumed.

Questions 1-4

Choose the correct heading for paragraphs B, C, D and E from the list of headings below.

List of Headings i. The first clue — calls differ by predator ii. The original assumption about alarm cries iii. Encoding features within a single call iv. Why skeptics still withhold the word "language" v. What it means for the origins of language vi. How hawks hunt prairie dogs vii. The anatomy of a prairie dog

1. Paragraph B: ____
2. Paragraph C: ____
3. Paragraph D: ____
4. Paragraph E: ____

Questions 5-8

Choose the correct letter, A, B, C or D.

5. What was the traditional assumption about prairie-dog alarm calls? A. They described individual predators in detail. B. They were simply emotional cries of danger. C. They were a form of grammar. D. They were used only at night.

6. How did the colony react to a hawk call? A. They scanned the ground and stood on their hind legs. B. They dived straight into the nearest burrow. C. They approached the hawk in a group. D. They ignored the call.

7. In the dog experiments, what varied within the calls? A. Only the volume, never the pitch. B. Details such as size, colour and shape of the dog. C. The time of day the call was made. D. Nothing at all — the calls were identical.

8. What key ability do skeptics say prairie dogs lack? A. The ability to hear high-pitched sounds. B. Displacement — referring to things not present. C. The ability to call in groups. D. Fear of predators.

Questions 9-13

Do the following statements agree with the claims of the writer?

Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this

9. Slobodchikoff's team analysed the calls using visual sound plots called spectrograms.
10. A coyote call typically sent every animal diving straight into a burrow.
11. Skeptics agree the calls are predator-specific but dispute the claim of flexible, word-like encoding.
12. Prairie dogs can discuss events that happened on a previous day.
13. Prairie dogs are native to North America.

Questions 14-15

Complete the summary below using NO MORE THAN TWO WORDS from the passage.

Prairie dogs produce predator-specific calls that listeners interpret as (14) ________ signals referring to external objects, though skeptics argue that without grammar and (15) ________, they should not be called a true language.

答案与解析

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