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TV AND WEB RESTRICTIONS~**PART MUST COURTESY BROWN UNIVERSITY The bat is the only mammal capable of true flight - an ability that might be linked to its highly effective immune system according to researcher, Ian Mendenhall of Duke-National University in Singapore. Today, he is taking samples from a fruit bat. He's looking specifically for viruses. SOUNDBITE: IAN MENDENHALL - RESEARCH FELLOW AT DUKE-NATIONAL UNIVERSITY OF SINGAPORE IN EMERGING INFECTIOUS DISEASES, SAYING: "When we're catching live bats, we typically take an oral swab, an anal swab, some feces and also some blood. Most pathogens have a particular cell tropism, or an affinity where they like to infect specific cells, so if we sample the mucus membranes, there are specific viruses that we expect to find there." These viruses include influenza, SARS and Ebola that can be fatal to humans and other mammals but have almost no effect on the bats.. Back at the lab, Mendenhall and his colleague Wang Lin-Fa are trying to find out why. They see clues in the bat's ability to fly. Flying takes a great deal of energy, and generating that energy requires a high metabolism. . But as it's producing energy for flight, the bat's metabolism is also producing toxic by-products called free radicals that damage DNA. However, the bat has developed a defence mechanism. Through analysis of the bats' genome, the researchers think they may have found the key. SOUNDBITE: WANG LIN-FA - DUKE-NATIONAL UNIVERSITY OF SINGAPORE PROGRAM DIRECTOR OF EMERGING INFECTIOUS DISEASES, SAYING: "Some genes involved in DNA damage repair also play a role in the immunity, so immunity is very important for our body to fight infection. So what we think is that explains bats carry a lot of deadly viruses, but they don't develop the disease when humans or animals do." With the help of international researchers the team plans to map these DNA variants within the next five years - in the hopes that the bat will lead the way to new preventive and controlling measures for emerging infectious diseases in vulnerable animals, including livestock…and humans. .