Always listening: the research could explain how bats hunt in groups

As if flying around in the dark swooping and diving to catch insects was not tricky enough, bats also listen for their fellow hunters.

A study has revealed how these winged mammals recognise other bats’ voices.

They are able to differentiate the ultrasonic “echolocation” calls that other bats make as they navigate.

In the journal PLoS Computational Biology, the scientists report that the bats have an internal “reference” call to which they compare others.

Yossi Yovel from the Weizmann Institute of Science, Israel, and his colleagues in Germany recorded the echolocation calls of five greater mouse-eared bats

The bats use these brief bursts of sound in sonar navigation - bouncing sound waves off their surroundings to find their way and locate prey.

Dr Yovel’s team tested the bats’ ability to identify the others by playing the recorded sounds to them.

“Each bat was assigned two others it had to distinguish between,” Dr Yovel explained. “So we trained bat A on a platform, playing a sound from bat B on one side and from bat C on the other. He had crawl to where the ‘correct’ sound was coming from.”

Each of the subjects was taught that a call from just one of the other bats was correct.

The bat chooses which sound to follow and which platform to crawl along

So during this training exercise, if the bat A made the right choice, and crawled towards the sound from bat B, it was rewarded with its favourite food - a mealworm.

“Then, in the next stage - the test - we rewarded them no matter what choice they made, and they still chose correctly more than 80% of the time,” said Dr Yovel.

“So we knew the bats were able to distinguish individuals. But it wasn’t clear what they’re using to discriminate one from the other.

“If you think of this in comparison with humans, it’s like being able to recognise a person just by listening to the same one-syllable yell in different voices.

“The bats learned the voice by listening to hundreds of very short ‘yells’, but they then were able to recognise an individual based on one single yell.”

Modelling sound

In the second part of the study, Dr Yovel’s team designed a computer model to mimic the way in which the bats compared the different sounds.

“The model takes all the calls the bat thought were A, and all the calls it thought were B, and tries to understand what differences it is using to match them up,” said Dr Yovel.

“Our analysis showed that each bat has a typical distribution in the frequencies it emits, probably a result of the differences in each animal’s vocal chords.”

He thinks the bats may have an internal “prototype” - a sort of reference sound against which they can compare these subtle differences.

This could explain how bats remain in a group when flying at high speeds in darkness, and how they avoid interference between each others’ echolocation calls.

Lebanese voters went to the polls Sunday in a crucial election that will determine whether the Middle Eastern country, scarred by war and political instability, picks a coalition supported by the United States or an alliance backed by the militant group Hezbollah.

Lebanese Prime Minister Foad Siniora casts his vote at a polling station in southern Lebanon.

Polls opened at 7 a.m. local time (12 a.m. ET) and will stay open for 12 hours. It is the first time the parliamentary elections are taking place all in one day rather than spread out over a few weekends.

Turnout was high among the country’s 3 million registered voters. About 50,000 troops were on the streets, but the run-up to the balloting had been free of violence.

At stake are 128 seats. And analysts say the race will be tight, with the Hezbollah-dominated “March 8 alliance” possibly winning a majority of seats in parliament.

Results are not expected at least until noon Monday.

Former U.S. President and Nobel Peace Prize Winner Jimmy Carter said Sunday that the United States should work with whichever coalition wins — even though it considers Hezbollah, which is supported by both Syria and Iran, to be a terrorist organization.

Carter, who was in Beirut among 200 international observers monitoring the election, oversaw balloting in Gaza during the elections in the Palestinian territory in January 2005.

The Palestinian militant group Hamas won that race “fairly and squarely” by a huge margin, Carter said. The United States and Israel later refused to recognize the legitimacy of the Hamas win.

“The Hamas candidates were approved in advance by both Israeli government and the American government. But when they prevailed, then Israel and the United States decided that they would not support a unity government,” he said.

“And it’s resulted in a split in the Palestinians and a very difficult situation there,” Carter added. “I think they (the United States) learned a hard lesson that they should accept the results of an election.”

Two senior Obama administration officials — Secretary of State Hillary Clinton and Vice President Joe Biden — have visited Lebanon in recent months, signaling concerns over a possible Hezbollah victory.

Hezbollah grew in popularity after its militant wing claimed victory over Israel after a 34-day military conflict in 2006. Since then, it has been more widely perceived by its supporters to be the “defenders” of Lebanon.

Even if a Hezbollah-dominated government does move in, it could have trouble working with Christian and Sunni Muslim politicians who — under Lebanese law — must participate in the government.

In Lebanon’s unique power-sharing government, the presidency is reserved for Maronite Christians, the speaker of parliament is always a Shia Muslim, and the prime minister is a Sunni Muslim. The law was created to balance power among Lebanon’s three main religious groups.

It will be difficult to find a Sunni political figure willing to serve as prime minister in a Hezbollah-led government since the majority of Lebanon’s prominent Sunni politicians are aligned with Saad Hariri, who leads the Sunni-dominated “March 14 coalition.”

Hariri’s coalition has declared it will not participate in any government if Hezbollah wins.

Resident Georges Azzi, who cast his ballot early Sunday morning, hoped the elections bring about a smooth and healthy transition to a new government and the continued support of the West — whatever the results.

“I think it would be seen as a punishment to everybody if it doesn’t,” Azzi said. “We should accept the results whatever they are. That’s how democracy works.”

Israeli Prime Minister Benjamin Netanyahu will deliver a major speech next week in which he will lay out his plan for the country’s peace and security.

Netanyahu made the announcement at the start of the weekly Cabinet meeting Sunday.

“We want to achieve peace with the Palestinians and with the countries of the Arab world, while attempting to reach maximum understanding with the U.S. and our friends around the world,” he said.

“My aspiration is to achieve a stable peace that rests on a solid foundation of security for the State of Israel and its citizens.”

Netanyahu did not say exactly when he will make the speech.

The speech follows an address to the Muslim world by U.S. President Barack Obama on Thursday where he took on the heated and controversial Palestinian-Israeli conflict by endorsing a two-state solution and urging compromise between “two peoples with legitimate aspirations.”

Calling America’s “strong bond” with Israel “unbreakable,” he said, “it is based upon cultural and historical ties, and the recognition that the aspiration for a Jewish homeland is rooted in a tragic history that cannot be denied.”

But, Obama said, “it is also undeniable that the Palestinian people — Muslims and Christians — have suffered in pursuit of a homeland.”

“For more than 60 years they have endured the pain of dislocation. Many wait in refugee camps in the West Bank, Gaza, and neighboring lands for a life of peace and security that they have never been able to lead,” he said.

A 28-year-old Oregon woman has been charged with murder after the body of a pregnant woman was found in her home.

Rescue crews first went to Korena Roberts’ home in Washington County on Friday in response to a call of a newborn in distress. They found Roberts’ boyfriend unsuccessfully trying to revive the baby using first-aid techniques.

Roberts told deputies the baby was hers, the county sheriff’s office said. Medics noticed a lot of blood at the home, and sent Roberts and the baby to a hospital.

“Doctors at the hospital could not revive the baby,” said Sgt. David Thompson of the Washington County Sheriff’s Office. “They also discovered that Ms. Roberts had not delivered the baby at anytime in the recent past.”

Deputies returned to the home, where they found the body of 21-year-old Heather Snively in the crawl space beneath the kitchen, Thompson said.

Authorities learned Snively had been pregnant at the time she was attacked, and they determined she was the mother of the newborn.

An autopsy will now determine how the baby was delivered, and whether he died before or after birth, Thompson said.

The outcome could result in another murder charge for Roberts, deputies said.

Residents in the woman’s Mill Creek Drive neighborhood said Roberts had told them she was expecting a child, according to CNN affiliate KPTV.

“She didn’t appear to be pregnant to us,” neighbor Doug King told KPTV.

Reality TV star Heidi Pratt was hospitalized Saturday in Costa Rica, her publicist confirmed.

Heidi Pratt was taken to a hospital for an undisclosed illness, her publicist said Saturday.

The details about Pratt’s hospitalization were not immediately available.

Pratt, star of MTV’s “The Hills,” has been competing on NBC’s “I’m a Celebrity … Get Me Out of Here,” a reality show about surviving the jungle.

Pratt and her husband, Spencer, tried to quit the show earlier in the week, but later decided to return.

“We realized that we made a big mistake and that the devil got to us and said, ‘Get out of the jungle,’” Pratt said. “We realized it’s not even about us.

“It’s about the charity, and it’s about the experience here and we took that for granted,” she said.

Roger Federer takes on Robin Soderling, who knocked out tournament favorite Rafael Nadal in a fourth-round stunner, in the men’s final of the French Open on Sunday.

Roger Federer screams in joy after beating Juan Martin del Potro to reach the French Open final.

A victory in Roland Garros would give Federer 14 Grand Slams, tying his career wins to American Pete Sampras.

The second-seed Federer lagged at first, but beat Argentine Juan Martin del Potro on Friday to make the final. Soderling advanced over Chilean Fernando Gonzalez.

Federer, 27, has a 9-0 record over the 24-year-old Swede going into the final.

The Swiss star has suffered emotional defeats recently.

At England’s Wimbledon last year, he lost to Rafael Nadal after a five-year reign. The game, which ran about seven hours with a few rain breaks, was the longest-ever Wimbledon men’s final.

Nadal also beat Federer in the Australian Open earlier this year.

Soderling stunned the top-seed Nadal by handing him a loss in the fourth round of the French Open.

The 23rd-seed Soderling was a rank outsider against the world number one who had never lost a match on the clay at Roland Garros and was a short-priced favorite to win a record fifth straight title.

In women’s tennis, number one Dinara Safina was beaten Saturday in straight sets by fellow Russian Svetlana Kuznetsova in the final of the French Open at Roland Garros.

Safina, who has reached the top of the world rankings despite not having a major title to her name, looked completely out-of-sorts against her compatriot, who secured a comfortable 6-4, 6-2 victory in just over an hour.

The defeat was a crushing blow to Safina, 23, who has long had to contend with the accusations that she is not a worthy world number one — and this third grand slam final defeat will do nothing to silence the doubters.

It was the second straight year she has lost in the final here, after going down in straight sets to Ana Ivanovic of Serbia last year.

It was also her second successive grand slam final defeat, having lost to Serena Williams in the Australian Open in Melbourne earlier this year.