️<unk>️<unk>️<unk>️  ️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️ However, new research has suggested that male birds may actually be growing less distinct from their female counterparts over time.<unk> However, new research has suggested that male birds may actually be growing less distinct from their female counterparts over time. ️<unk>️<unk>️<unk>️<unk>️<unk>️ Male and female Choco Toucan's (pictured above) both share the same brightly colored plumage, suggesting another force other than sexual selection is driving the evolution of bright colors in feathers of some birds.<unk> Male and female Choco Toucan's (pictured above) both share the same brightly colored plumage, suggesting another force other than sexual selection is driving the evolution of bright colors in feathers of some birds.<unk> Male and female Choco Toucan's (pictured above) both share the same brightly colored plumage, suggesting another force other than sexual selection is driving the evolution of bright colors in feathers of some birds. Rather than the bright colors of male birds appearing because of sexual selection - where a trait evolves over time because it is seen as attractive or a signal of fitness by the opposite sex - other forces of natural selection are at work. Researchers say that the environment a species lives in, how it cares for its young and migratory behavior appear to influence a species plumage.<unk> Researchers say that the environment a species lives in, how it cares for its young and migratory behavior appear to influence a species plumage. ️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️ Scientists have shown that peacocks shake their tails to make a noise that is too low for us to hear. Male birds may make the infrared rumble to scare off an approaching rival or to attract a mate.<unk> Male birds may make the infrared rumble to scare off an approaching rival or to attract a mate. Researchers at the University of Manitoba in Winnipeg, Canada, have shown that the birds make infrasound noises - below 20 hertz - using their tails and that other peacocks respond to them. Most humans hear sounds between 20 and 20,000 hertz.<unk> Most humans hear noises between 20 and 20,000 hertz. When peacocks shake their tale feathers, most humans hear a rustling sound.<unk> When peacocks shake their tale feathers, most humans hear a rustling sound. But the scientists found that the birds hear a loud sound of between 70 and 108 decibels, according to the study published in the journal Animal Behaviour. Male and female peacocks became more alert and moved around when the low noises were played back to them by researchers, with males shrieking out in response.<unk> Male and female peacocks became more alert and moved around when the low noises were played back to them by researchers, with males shrieking out in response. Experts are uncertain how the birds detect infrasound, but know that some can feel vibration through... (Experts are uncertain how the birds detect infrasound, but know that some can feel vibration through...
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