A little more on the research - <a href="http:&#x2F;&#x2F;www.exeter.ac.uk&#x2F;news&#x2F;featurednews&#x2F;title_488900_en.html" rel="nofollow">http:&#x2F;&#x2F;www.exeter.ac.uk&#x2F;news&#x2F;featurednews&#x2F;title_488900_en.ht...</a> including why it&#x27;s difficult to do this in the wild. And some earlier research <a href="http:&#x2F;&#x2F;news.bbc.co.uk&#x2F;1&#x2F;hi&#x2F;8631486.stm" rel="nofollow">http:&#x2F;&#x2F;news.bbc.co.uk&#x2F;1&#x2F;hi&#x2F;8631486.stm</a> with video.