Lions are often incorrectly called the “king of the jungle”. These days, the giant cats are not feared as much as another “super predator (捕食者)”—the animals living in South Africa now fear humans more than lions, according to a study published recently. 【小题1】

The study focused on Greater Kruger National Park in South Africa. Scientists set up speakers and cameras around 21 waterholes in the dry season between June and August. The researchers chose the site since waterholes are known as a small pool of water where animals drink. 【小题2】 This makes waterholes a popular hunting spot for both lions and poachers (偷猎者).

During the experiment, the researchers played different sounds. These included lions roaring, and humans speaking calmly in local languages. The study found that animals were twice as likely to run away from a human voice than a lion sound. 【小题3】 The results suggest that animals have learned that being close to humans can be dangerous because they might be poachers. This could pose a problem to national parks that depend on making money from safari tourism. 【小题4】

【小题5】 Endangered species, such as the southern white rhino (犀牛), could be protected by using recorded human voices. For instance, rhinos abandon waterholes much quicker when they hear human voices over other sounds, which could help to drive the frightened species away from places where poachers are known to lie in wait.

Sharks have lived in the world’s oceans for millions of years. A shark has a very good sense of smell. It can find small amounts of substances in water, such as blood, body liquids and chemicals produced by animals. These powerful senses help sharks find their food. 【小题1】

Sharks grow slowly. About forty percent of all sharks lay eggs. 【小题2】 Some sharks carry their young inside their bodies as humans do. Some sharks are not able to reproduce until they are twenty years old. Most reproduce only every two years. And they give birth to fewer than ten young sharks. For this reason, over-fishing of sharks is of special danger to the future of the animal.

【小题3】 They eat injured and diseased fish. Their hunting activities mean that the numbers of other fish in ocean waters do not become too great. This protects the plants and other forms of life that exist in the oceans.

People hunt sharks for sport, food, medicine and their skin. Experts say the international market for some kinds of sharks has increased because many parts of a shark are valuable. 【小题4】 Shark liver oil is a popular source of vitamin(维他命).The skin of a shark can be used like leather. In Asia, people enjoy a kind of soup made from shark fins. Experts say a fisherman can earn a lot of money for even one kilogram of shark fins.

Sharks are among the oldest animals on Earth. 【小题5】 If too many sharks in one area are killed, the group of sharks may never return to normal population levels.

Humans have sailed the oceans’ surfaces for thousands of years, but their depths remain effectively uncharted. Only about a quarter of the seafloor has been mapped at high resolution (清晰度). Maps of most regions display only estimated depths and often miss entire underwater mountains or canyons (峡谷). So a group of researchers have turned to some deep-diving experts: Elephant Seals and Weddell Seals. Scientists have been placing trackers on these blubber y marine mammals around Antarctica for years, gathering data on ocean temperature and salinity (盐度).

For a new study, the researchers compared these dives’ location and depth data with some of the less detailed seafloor maps. They spotted places where the seals dove deeper than should have been possible according to the maps.

In eastern Antarctica’s Vincennes Bay, the diving seals helped the scientists find a large, hidden underwater canyon suddenly descending (下降) to depths of more than a mile. “The seals discovered the canyon, and the ship confirmed it,” says Clive McMahon, a researcher at the Integrated Marine Observing System in Australia and a co-author of the new study.

But seals can’t map the entire ocean floor. The trackers used in the study could pinpoint (为……准确定位) a seal’s geographical location only within about 1.5 miles, which allows for useful but not exactly high-resolution data. Plus, because the seals don’t always dive to the bottom of the ocean, they can reveal only where the bottom is deeper than in existing maps — not shallower. McMahon notes that scientists could improve on these data by using more precise GPS trackers and analyzing the seals’ diving patterns to determine whether they have reached the seafloor or simply stopped descending.

The current seal-dive data can still be valuable for an important task, says Anna Wåhlin, an oceanographer at the University of Gothenburg in Sweden. The deep ocean around Antarctica is warmer than the extremely cold waters at the surface, and seafloor canyons can allow that warmer water to flow to the ice along the continent’s coast, Wåhlin explains. To predict how Antarctica’s ice will melt, scientists will need to know where those canyons are and how deep they go.