The biggest and the smallest of the world’s animals are most at risk of dying out, according to a new analysis, with vertebrates (脊椎动物) in the so-called “Goldilocks zone”—not too big and not too small—winning out. Action is needed to protect animals at both ends of the scale, they say. The research adds to evidence that animals are dying out on such a scale that a sixth extinction is considered under way.
One clue is body size. Research on birds and mammals has shown that those with larger bodies are more likely to go extinct. Yet, when the researchers made a database of thousands of birds, mammals, fish, amphibians (两栖动物) and reptiles (爬行动物) at risk of extinction, they found disproportionate (不成比例的) losses at the large and small ends of the scale.
“Surprisingly, we found that not only the largest of all vertebrate animal species are most threatened, but the very tiniest ones are also highly threatened with extinction,” Prof. Ripple told BBC News.
Large animals, such as elephants, rhinos (犀牛) and lions have long been the target of protection efforts. However, fish, birds, reptiles and amphibians that are the giants of their kind, such as the whale shark, Somali ostrich (鸵鸟) and the Chinese giant salamander (蝾螈), tend to be overlooked. Meanwhile, small species at risk--such as frogs and shrews (鼩鼱)--receive very little attention.
“I think, for the smallest species, first of all we need to bring higher awareness to them, because the larger ones get a lot of attention, but the smaller ones get very little,” said Prof. Ripple.
In the study, vertebrates with the smallest and the largest bodies were found to be most at risk of disappearing, whether they were on land or living in oceans, streams or rivers.
Heavyweights are threatened mainly by hunting, while featherweights are losing out to pollution and cutting down forests. “Ultimately, reducing global consumption of wild meat is a key step to reduce negative impacts of hunting, fishing, and trapping on the world’s vertebrates,” they write in Proceedings of the National Academy of Sciences.
1. What made the researchers feel surprised?A.A sixth of animals are dying out. |
B.Small animals are in great danger. |
C.Great losses of birds and mammals. |
D.Big animals are at risk of disappearing. |
A.Transform our habits. | B.Change our concepts. |
C.Find ways to save small animals. | D.Take measures to stop pollution. |
A.Loss of forests. | B.Climate change. |
C.Human activities. | D.Environmental pollution. |
A.Size Matters When It Comes to Extinction Risk |
B.Large Animals Are Badly in Need of Protection |
C.Why a Great Number of Animals Are Dying out |
D.What We Should Do to Protect Endangered Species |
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【推荐1】Every year more people recognize that it is wrong to kill wildlife for “sport”. Progress in this direction is slow because shooting is not a sport for watching, and only those few who take par realize the cruelty and destruction.
The number of gunners, however, grows rapidly. Children too young to develop proper judgments through independent thought are led a long way away by their gunning parents. They are subjected to advertisements of gun producers who describe shooting as good for their health and gun-carrying as a way of putting redder blood in the veins(血管). They are persuaded by gunner magazines with stories honoring the chase and the kill. In school they view motion pictures which are supposedly meant to teach them how to deal with arms safely but which are actually designed to stimulate(刺激)a desire to own a gun.
Wildlife is disappearing because of shooting and because of the loss of wildland habitat Habitatloss will continue with our increasing population, but can we slow the loss of wildlife caused by shooting? There doesn't seem to be any chance if the serious condition of our birds is not improved. Wildlife belongs to everyone and not to the gunners alone. Although most people do not shoot, they seem to forgive shooting for sport because they know little or nothing about it. The only answer, then, is to bring the truth about sport shooting to the great majority of people.
Now, it is time to realize that animals have the same right to life as we do and that there is nothing fair or right about a person with a gun shooting the harmless and beautiful creatures. The gunners like to describe what they do as character-building, but we know that to wound an animal and watch it go through the agony of mortality can make nobody happy. If, as they would have you believe, gun-carrying and killing improve human character, then perhaps we should encourage war.
1. According to the text, most people do not seem to be against hunting because .A.they have little knowledge of it. |
B.it helps to build human character. |
C.it is too costly to stop killing wildlife. |
D.they want to keep wildlife under control. |
A.difficulty. | B.tress. | C.pain. | D.sadness. |
A.teach them how to deal with guns safely. |
B.praise hunting as character building. |
C.describe hunting as a physical exercise. |
D.encourage them to have guns of their own. |
A.Hunting to build human character makes no sense. |
B.War in the best way to improve human character. |
C.We are on the edge of war against gunners. |
D.Protecting wildlife from gunners is extremely difficult. |
【推荐2】In early February 2019, 51-year-old Rainer Schimpf and his team set out to film South Africa’s Sardine Run off the coast of Point Elizabeth Sardine Run, the annual migration(迁徙)of billions of sardines (a small sea fish), is a big draw for large predators, especially the dolphin and whale. Predators are animals that kill and eat other animals. In an attempt to obtain the best images of the incredible natural phenomenon, Rainer dived into the middle of a spinning ball of fish. Suddenly the sea moved around violently, and the experienced diver and his photographer Heinz Toperczer, who was filming from the boat, instantly realized something strange was going on Suddenly dolphins shot out of the water, a white spray came out and then a whale appeared and grasped Rainer
While Toperczer was filming the terrifying turn of events with his video camera, Rainer, who was trapped had first and engulfed(吞噬)in darkness inside the whales mouth, was trying to survive. Nothing can actually prepare you for the event when you end up inside the pure instinct(本能), "the diver told Barcroft TV. “Knowing in the whale’s mouth, I tried to control my fear. But I was convinced that it was going to dive down and release me much deeper in the ocean.”
The whale quickly realized he was no sardine! As the whale turned sideways, he opened his mouth slightly to release me, and I was washed out, together with what felt like tons of water, of his mouth, " recalled Rainer. Though the entire incident lasted just 1. 8 seconds, it felt like a year to Rainer.
Still holding his underwater camera in his hand. the diver swam to his boat, where he was quickly rescued by the members of the team. The terrible adventure did not disturb Rainer for too long. After checking to ensure he had no injuries, the diver returned to the water to seek out more
1. Which of the following is the best title of the passage?A.A Diver's Narrow Escape From A Whales Mouth |
B.The Annual Migration Of Billions Of Sea sardines |
C.A Frightening And Fantastic Experience Under Sea |
D.An Adventurous Trip Off Coast Of Point Elizabeth |
A.seagull | B.Seals | C.Dolphins | D.tortoises. |
A.He dived aimlessly | B.He cried desperately. |
C.He panicked immediately. | D.He struggled violently. |
A.intelligent | B.generous | C.flexible | D.fortunate |
【推荐3】Lots of people dream of a beach vacation, but hesitate to take one because they don't want to leave a pet behind.
Find a hotel that is pet-friendly. Most hotels that accept pets will advertise themselves as pet-friendly on their websites.
Clean up after your pet. When vacationing with your pet it doesn't mean that all responsibility is gone. Picking up after it, whether that is when it goes to the bathroom or it makes a mess with its food, is still your responsibility.
Be considerate of others.
A.Protect your pet from the sun. |
B.Make sure you choose a beach that allows pets. |
C.However, there is no need to settle for a pet sitter. |
D.You never know how an animal will react in public. |
E.You could also try to stay with a friend who loves your pet. |
F.If you are unsure whether a hotel accepts pets, call it and ask. |
G.This is especially important at the beach where many people move around. |
【推荐1】I have had just about enough of being treated like a second-class citizen, simply because I happened to be that put-upon member of society ― a customer. The more I go into shops and hotels, banks and post offices, railway stations, airports and the like, the more I’m convinced that things are being run just to suit the firm, the system, or the union. There seems to be a new motto for the so-called “service” organization ― Staff Before Service. How often, for example, have you queued for what seems like hours at the Post Office or the supermarket because there aren’t enough staff on duty at all the service counters? Surely in these days of high unemployment it must be possible to increase counter staff. Yet supermarkets, hinting darkly at higher prices, claim that bringing all their cash registers into operation at any time would increase expenses. And the Post Office says we cannot expect all their service counters to be occupied “at times when demand is low”.
It’s the same with hotels. Because waiters and kitchen staff must finish when it suits them, dining rooms close earlier or menu choice is lowered. As for us guests (and how the meaning of that word has been cut away little by little.), we just have to put up with it. There’s also the nonsense of so many friendly hotel night porters having been gradually withdrawn from service in the interests of “efficiency” (i.e. profits) and replaced by coin-eating machines which supply everything from beer to medicine, not to mention the creeping(慢慢加剧的) threat of the tea-making set in your room: a kettle with teabags, milk bags and sugar. Who wants to wake up to a raw teabag? I don’t, especially when I am paying for “service”.
Our only hope is to repeat our anger whenever and wherever we can and, if all else fails, restore that other, older saying ― Take Our Custom(买卖) Elsewhere.
1. The author feels that nowadays customers are _____.A.not provided with proper service |
B.considered to be lower members of society |
C.not worthy of special treatment |
D.regarded as privileged |
A.more consideration is given to the staff than customers |
B.customers are becoming more demanding |
C.customers are unwilling to be satisfied with |
D.the staff are less considerate than employers |
A.deliberate(故意的)understaffing |
B.lack of cooperation among staff |
C.the reducing supply of good staff |
D.inefficient staff |
A.the personal touch is less appreciated nowadays |
B.few people are willing to do this type of work |
C.machines are more reliable than human beings |
D.self-service provides a cheaper alternative |
A.to put up with whatever service is provided |
B.to fully use all kinds of coin-eating machines |
C.to make strong complaints wherever necessary |
D.to go where good service is available |
【推荐2】The UN this week launched a report urging companies to stop issuing false net-zero targets that amount to greenwashing.
Greenwashing is a term used to describe situations where companies mislead consumers by claiming to be eco-friendly or sustainable as a marketing plan rather than as a core principle of their business model. Often, these industries spend more money making themselves appear sustainable than they do taking actual sustainable measures into their company.
Cities, financial institutions, and scores of companies have announced plans to reduce their emissions to zero, which, in principle, should help the fight against climate change.
“The problem is that the criteria for these net-zero commitments have varying levels of precision and loopholes (漏洞),” said UN Secretary-General Antonio Guterres during the launch of the report.
Many net-zero plans contain far-away or unclear targets and often call for the use of unproved technologies like carbon capture and tree planting, which effectively allow companies to continue polluting the atmosphere. Studies show that most of these net-zero plans will do little to stop temperatures from rising. For example, many oil majors have announced plans to reduce emissions from their operations to zero by 2050 that do not take into account the carbon emitted by the fossil fuels they sell, which would allow them to increase production. Far from decreasing, fossil fuel production is going strong.
To close these net-zero loopholes, the UN this week released a report that includes 10 recommendations to ensure that companies, cities, regions, and other non-state actors issue credible and accountable net zero commitments. “Their plans cannot rely on cheap carbon credits instead of immediately cutting their own emissions,” Guterres said.
Financial institutions need to cut down emissions from all their investments and businesses need to bring down the carbon footprint of their supply chain, the report said. The report’s lead author, Catherine McKenna, urged companies to release new net-zero targets within a year. The updated targets must contain concrete actionable details.
1. What does “greenwashing” refer to?A.A green technology. | B.A misleading statement. |
C.A business model. | D.A spending target. |
A.To prove oil majors are really responsible. |
B.To set some good examples for other companies. |
C.To show some net- zero commitments make no sense. |
D.To indicate the benefit of net zero plans to climate change. |
A.Dissatisfied. | B.Guilty. | C.Shocked. | D.Confused. |
A.Plant more trees. | B.Share more supply chains. |
C.Depend on cheap carbon credits. | D.Make concrete actionable targets. |
【推荐3】How far would you go for your kids education? That 's a question many parents are asking in the wake of the college cheating scandal(丑闻)involving 38 wealthy parents around the country, including actresses Lori Loughlin and Felicity Huffman. Here’ s how far I went. In the fall of 2017 my husband and I lost our jobs. We had to tell our daughter, Casey, that we couldn’t afford to send her back to school for her junior year at Fordham University. We decided the best choice for our family would be for Casey to sit out a year. We promised that we would get her back the following year. Casey decided to spend the year volunteering in South Africa On Sept 30, 2017, we put our oldest child on a plane halfway around the world. Casey worked as a tutor teaching kids math, English and music in Johannesburg. We did get Casey back in school in time. When she returned to the campus, she studied harder. She isn't what she used to be. Each day is marked by gratitude because she knows what it is like not to be able to get an education.
I wonder why the college cheating scandal happened and I think it boils down to this: Parents want to create a comfort zone for their kids. Of course, we want the best for our kids but sometimes we forget that real growth doesn't happen in times of comfort; those valuable lessons come when we are forced to think in ways we otherwise wouldn’t have
While I did less for my child than these wealthy parents did in terms of means, in other ways I did more. I taught her that disappointment is a part of life and we should face it bravely rather than avoid it. My husband and I showed Casey that her strength is in her struggle. That's how far I went for my kid s education. And I dare say she is wiser and better off for it.
1. What do the parents involved in the college cheating scandal have in common?A.They are well –known | B.They are aggressive |
C.They are very rich | D.They are conservative. |
A.for lack of money | B.because of her illness |
C.as a result of cheatings | D.due to her bad behaviour |
A.It’ s meaningless. | B.It is well worth it. |
C.It is a waste of time | D.It is a wrong decision. |
A.create a comfort zone for their kids | B.do whatever they can for their kids |
C.help their kids have a better education | D.let their kids experience disappointment |
【推荐1】Here are four pieces of news from China Daily.
SHANGHAI — The Huachen Group recently held a meeting in Shanghai to show the use of its newly opened tourism business payment network. The network aims to serve tourists from all over the world, but especially from Europe and the United States where credit cards are popularly used. After opening the www.chinaecnet.com website, netizens can get information about hotels and tourism services on tourism page. Hotels and services can be reserved and payments made through credit cards. The network opened in February in Beijing.
SYDNEY — The Sydney Olympic flame will travel underwater on Australia’s Great Barrier Reef during the torch relay following a successful test. Scuba diver Wendy Craig, a marine biologist, will carry the torch on a three-to-four-minute underwater journey at Agincourt Reef on June 27, creating Olympic history, organizers said yesterday. Burning at 2000 degrees, the torch is expected to remain a light three meters underwater because of the special technology which creates a fierce flame that can not be drowned out by water.
Charles Tegner, managing director of torch creator, said the flame would burn like a flare (照明弹) from oxygen-producing chemicals.
BEIJING — The election of a new leader in Taiwan can not change the fact that Taiwan is a part of Chinese territory. “Taiwan Independence” in whatever form will never be allowed, according to a statesman of China’s central government.
“We should listen to what the new leader in Taiwan says and watch what he does. We will observe where he will lead cross-Straits (海峡两岸) relations. We are willing to exchange views on cross-Straits relations and peaceful reunification with all parties, organizations and personages in Taiwan who favor the one China principle,” says the statesman, which was released by the Taiwan Affairs Office of the CPC Central Committee.
HAIKOU — Customs officers in Haikou recently stopped a boat loaded with 781 cases of foreign-brand cigarettes being smuggled (走私) into China. The smuggled cigarettes cases, packed into two containers, were disguised to avoid being examined. The boat was registered in the coastal city of Xiamen in East China’s Fujian Province. All eight suspects aboard the boat were kept by the police in Haikou.
1. Why does the network aim to serve tourists especially from Europe and the USA?A.Because they are from developed countries. |
B.Because the payments of hotels and services should be made through credit cards. |
C.Because people in these countries travel much more than other countries. |
D.Because it is more convenient for them to surf the Internet. |
A.The whole torch relay will be held three-four metres underwater. |
B.The underwater journey of the torch will play an important part in Olympic history. |
C.A test has been made before this activity. |
D.Some chemicals will help the flame burn by producing oxygen. |
A.Ready to Fight |
B.No Good End |
C.Wait and See |
D.Peace Comes First |
A.made different from normal |
B.designed for a good purpose |
C.divided |
D.pretended |
【推荐2】Thirty female contestants, all older than 30, took part in a reality show this summer, competing for five places in a performance group.
The program immediately became a hot topic nationwide, as the entertainment industry in China traditionally favors women in their early 20s or even younger.
Named Sisters Riding the Winds and Breaking the Waves, the show premiered (首映) on June 12 on Hunan Television and Mango TV, a livestreaming platform.
Actresses Ning Jing, 48, and Christy Chung, 50, along with singers Zhang Hanyun, 31, and Yu Kewei, 37, were among the contestants. A panel (专门小组) of coaches joined the show, including a well-known actor, the head of a music company, a celebrity manager, a music director and a stage director.
The first episode attracted more than 15 million viewers and sparked heated debate online. The contestants showed their dancing and singing abilities with solo and group performances.
Yang Chang, who works for a media company in Beijing, said: "Bringing these women together arguably contributed to making the most interesting reality show of the year. It sends a message that although we live in a youth-obsessed (着迷的) culture, there's still something to be said for the enduring appeal of women who are established and experienced."
Molly Tang, another fan of the show, who is approaching 30, said: "The women are very cool, fashionable and attractive. They have their own styles, rather than following a trend. I really admire their courage in breaking conventional stage or screen stereotypes (刻板印象)." She added that after watching the show, she is no longer afraid of becoming older.
1. Why did the program become a hot topic?A.Because the contestants are traditional. |
B.Because Hunan Television and Mango TV have huge influence on youngsters. |
C.Because the female contestants are all old. |
D.Because its contestants contrasted sharply with traditional shows. |
A.5 contestants will be the final winners and form a group. |
B.A music director and a stage director also joined in the show as contestants |
C.The contestants performed singly and cooperatively. |
D.Mr.Yang admitted that we live in a youth-obsessed culture. |
A.Mr. Yang is not a fan of the reality show. |
B.Mr. Yang favors the experienced entertainers more than the young ones. |
C.Miss. Molly is in her 30s. |
D.Miss. Molly got inspired and became more confident. |
A.The older people get, the more attractive they become. |
B.People get old, but gold will shine. |
C.Never follow the trend. |
D.It is never too old to learn. |
【推荐3】Katalin Karikó and Drew Weissman, who together identified a slight chemical change to messenger RNA,were awarded the Nobel Prize in Physiology or Medicine this year.
Dr. Karikó, the 13th woman to win the prize, had come to the United States from Hungary two decades earlier when her research program there ran out of money. She was preoccupied by mRNA, which provides instructions to cells to make proteins. Defying the decades old belief that mRNA was clinically unusable, she hold the view that it would stimulate medical innovations.
She and Dr. Weissman had their first chance meeting over a copy machine at the University of Pennsylvania in 1998. At the time, Dr. Weissman was desperate for new approaches to a vaccine (疫苗) against HLV, which bad long proved impossible to defend against. A physician who had tried and failed for years to develop a treatment for AIDS, he wondered if he and Dr. Karikó could team up to make an HIV. vaccine.
For years, they were at a loss. Mice vaccinated with mRNA became inactive. Countless experiments failed. They wandered down one dead end after another, But eventually, the scientists discovered that cells protect their own mRNA with a specific chemical modification (修饰). So they tried making the same change to mRNA manufactured in the lab before vaccinating it into cells It worked.
At first, other scientists were largely uninterested in taking up that new approach to vaccination. But two biotech companies soon took notice: Moderna, in the United States, and BioNTech, in Germany. Then the coronavirus emerged. Almost instantly, Drs. Karikó and Weissman’s work came together with several factors of different research to put vaccine makers ahead of the game in developing shot.
Brian Ferguson, an immunologist at the University of Cambridge, said. “The work of Katalin Karikó and Drew Weissman in the years prior to 2020 prevented tens of millions of deaths and helped the world recover from the worst pandemic in a century. They richly deserve this recognition.”
1. The underlined word “defying” (paragraph 2) is closest in meaning to “ ”.A.challenging | B.confirming | C.re-emphasizing | D.stating |
A.They teamed up for the treatment for AIDS in Hungary. |
B.They protected their mRNA with a chemical modification. |
C.They persevered until they made a change to lab-made mRNA. |
D.They manufactured mRNA in mice despite their countless failures. |
A.they took no notice of others’ ignorance |
B.they caught attention of two biotech companies |
C.their work helped avoid the loss of countless lives |
D.their work prevented the outbreak of the pandemic |
A.Chemical Changes Identified in the Pandemic |
B.Approaches Adopted to Defend Against HLV |
C.Nobel Prize Awarded to Covid Vaccine Pioneers |
D.mRNA Manufactured in a University Lab in USA |
【推荐1】Like producers of wine from France's Champagne area, Brazil's chocolate industry is using geographical indication, or GI labels with good results. These labels show where the cocoa comes from and its quality. The special labels can lead to higher prices on the market.
Henrique Almeida is the 63-year-old owner of a farm in Coaraci, in the northeastern Brazilian state of Bahia. He is pleased with the "South Bahia" geographical indication for his cocoa. "The production of fine cocoa and the creation of the geographical indication label make it possible to have a profitable business and pull our region upwards," Almeida said.
For many years, farmers in Bahia had produced common cocoa, used widely in the chocolate industry. But in 1989, an outbreak of "witches' broom" disease sharply reduced the productivity of Bahia's cocoa trees. These trees make up to 86 percent of Brazil's national crop. At the time, Almeida, like other producers in southern Bahia, chose to improve the quality of his crop in order to be able to continue growing.
"When I bought the farm, standard cocoa prices were low, and cocoa farmers were unmotivated(无动机的), while the chocolate market was doing well," he told the French news agency AFP. "I started growing fine cocoa to make my own chocolate and add value to my product."
The label is the result of 10 years of work by Almeida and other cocoa producers, as well as cooperatives and researchers. Together, they created the South Bahia Cocoa Association to define(定义)production rules. The National Institute of Industrial Property registered the GI 6 years after the first registered GI.
The “South Bahia” label is the second GI given to Brazilian cocoa. The Linhares region in the state of Espirito Santo was the first GI to be registered in 2012. Tome-Acu in the northeastern state of Para became the third in 2019.
1. What might be a result of witches' broom in 1989?A.Many cocoa trees in Brazil died. | B.Cocoa became quite expensive. |
C.Farmers started to grow fine cocoa. | D.Chocolate industry had to use common cocoa. |
A.In 2012. | B.In 2014. |
C.In 2016. | D.In 2018. |
A.A national cocoa association may appear quickly. |
B.Common cocoa may disappear soon. |
C.Cocoa fanners may apply for more GI labels. |
D.Cocoa prices will be higher and higher. |
A.Brazil's cocoa industry benefits from GI labels. |
B.Brazil's cocoa farmers are learning to make French wine. |
C.GI labels are making higher profits for Brazil's cocoa farmers. |
D.Better Brazil's cocoa trees will bring finer Brazil's cocoa. |
【推荐2】 The unique ocean animals were discovered by a team of scientists led by Dr. Christine Dudgeon from Australia’s University of Queensland during a 12 year global conservation study.
The newly-found sharks have evolved (进化) to survive in low oxygen environments, enabling them to hunt during low tides. The researchers believe their ability to use their fins (鳍) to walk affords the sharks a remarkable edge over the smaller animals they try to hunt. “While they are super hunters in their shallow habitat, the tiny sharks present no threat to people,” says Dudgeon. “At less than a meter long on average, they’re incredibly cute little animals that do not look like sharks at all,” she adds.
A DNA analysis of skin samples from the live fish suggests that walking sharks broke away from their original population and became a distinct species about nine million years ago. Though that may appear to be a long time ago, it is relatively recent given that sharks have been around for more than 400 million years. In fact, Dudgeon and her team believe walking sharks are the youngest kind of sharks on Earth!
The researchers say that the sharks’ small numbers and small habitat make them extremely vulnerable (易受伤害) to natural disasters and overfishing. They are currently on the Nature Red List, which lists species at risk. Dudgeon and her team believe sensible conservation management plans are urgently needed to protect the walking sharks and other endangered animals from further threats.
1. What is the most noticeable feature of the newly-found sharks?A.They are cute and harmless to humans. |
B.They can survive in their shallow habitat. |
C.They walk on their fins across the seafloor. |
D.They are the youngest kind of sharks on Earth. |
A.The evolution of the shark. |
B.The behavior of the sharks. |
C.The population of the sharks. |
D.The DNA samples of the sharks. |
A.Adjusting the methods of fishing. |
B.Putting the sharks on the Nature Red List. |
C.Changing the sharks’ living environments. |
D.Adopting necessary measures to protect the sharks. |
A.Environment. | B.Nature. |
C.Education. | D.Geography. |
【推荐3】Birds use vocalizations to attract mates, defend territories, and recognize fellow members of their species. But while we know a lot about how variations in vocalizations play out between populations of songbirds, it's far less clear how this variation affects birds such as penguins in which calls are inherited (遗传). A new study from The Auk: Ornithological Advances examines differences in the calls of Little Penguins from four colonies in Australia-night-time birds for whom vocalizations are more important than visual signals-and finds that differences in habitat, rather than geographic isolation (隔离) or other factors, seem to be the key driver of variation in the sounds these birds use to communicate.
Diane Colombelli-Negrel and Rachel Smale of Australia's Flinders University recorded calls from four Little Penguin populations across a small area of South Australia, one of which had previously been shown to have slight genetic differences from the other three, and used playback experiments to test penguins ability to distinguish between calls from different colonies.They found that agonistic calls, which are used in pair displays and aggressive situations, varied among the four populations, and that the calls' characteristics appeared to depend on small-scale differences in the habitat where the penguins lived. However, birds did not discriminate between calls originating from different colonies, which suggests that agonistic calls don't seem to play a role in isolating the two different genetic groups.
Penguins living in open habitats produced lower-frequency calls than those living in habitats with thicker vegetation-the opposite of the trend typically observed in songbirds. The authors think that agonistic calls may be subject to different selective pressures because they're used in close encounters with other birds rather than to communicate across distances, and could also be influenced by variation in the noise level of wind and surf.
“I was excited to find that in seabirds, as most of our knowledge in this area comes from studies on songbirds," says Colombelli-Negrel. "This new research suggests that many factors influence call variation in birds, which also depends on the function of the calls. This study highlights that many questions remain and that studies need to investigate more than one factor in conjunction with the function of the calls to fully understand call variation in seabirds.”
“This work tells an interesting story of vocal diversification in Little Penguins, and gives insight into how individual and micro-scale variation effects behavior," according to Stony Brook University's Heather Lynch, an expert on penguin calls who was not involved in the study. "Non-vocal-learning birds are relatively understudied in terms of vocalizations, and it is great to see penguin vocalizations being studied in such a way."
1. What does the new study find?A.Penguins are born with their calls. |
B.Penguins communicate by various calls. |
C.Penguins' calls are influenced by their habitat. |
D.Penguins' calls can help isolate genetic groups. |
A.The test of penguins' responses to recorded calls. |
B.The data collected from penguins across Australia. |
C.Controlled experiments on penguins and songbirds. |
D.Similarities between the calls of penguins and songbirds. |
A.open-space songbirds tend to lower their calls |
B.environmental noises may affect penguins' calls |
C.birds use agonistic calls in distant communication |
D.songbirds' agonistic calls vary little between species |
A.will keep track of penguins to preserve them |
B.have investigated a lot in penguins' calls before |
C.will have a broader look at differences in penguins' calls |
D.have determined the function of various calls in penguins |