The Cassowary: A Basal Bird

The cassowary has a structure on top of its head that is thought to be used in producing these deep, guttural booming sound. Both sexes of the cassowary have this cask on the top of their head, so both sexes do it. So it probably has some kind of social function - but we're not quite sure. The only way to open a plastic bag is to moisten your fingers to grip the two films of plastic? Everyone does that all the time. It's likely that it's surface tension which gives you an extra bit of stickiness.