Penguins being tracked by scientists have an attached tracking band which allows them to be found. There is a problem with these bands, though, as they induce drag while they swim, which causes them to not catch as much food. This is endangering many penguins!
Read more:
http://www.nytimes.com/2011/01/18/science/18obpenguin.html?_r=1&ref=science
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