It would have looked a bit like the time - honored mating signal. (discovermagazine.com)
Biden and Ryan stand on either side of that debate, and their selections as running mates signal vastly different approaches to winning the Catholic vote. (religion.blogs.cnn.com)
So scientists have been puzzled that males of many species, including fish and frogs, send mating signals that a female has trouble perceiving. (sciencemag.org)