The double compound eyes of a male St. Mark's fly (Bibio marci), submitted by Dr. David Maitland from Feltwell, UK. (Dr. David Maitland)

Eugloss dilemma, male, Florida, Biscayne National Monument. (Photo and caption by Sam Droege/USGS Bee Inventory and Monitoring Lab)

The cast of The Expendables, L-R: actors Jason Statham, Sylvester Stallone, Dolph Lundgren and Terry Crews attended the ringing of the opening bell at the New York Stock Exchange on Wall Street in NYC today. There is something so unsexy (not to mention suspect) about a male who constantly takes off his shirt to flex his muscles while in the company of other alpha males.

A woman in a wedding gown walks to a mass wedding ceremony, held 17 male inmates, in the Carcel Villa Hermosa prison in Cali, Colombia, August 19, 2016. (Photo by Jaime Saldarriaga/Reuters)

A male deer barks at dawn during the annual deer rutting season at Richmond Park in London, Britain, October 9, 2016. (Photo by Toby Melville/Reuters)

Khan, a five-year-old male White Bengal tiger, looks on inside an open-air cage at the Royev Ruchey zoo in Krasnoyarsk, Russia, October 21, 2016. (Photo by Ilya Naymushin/Reuters)

This huge male orangutan is having a right old laugh as he squints his eyes and shows his huge teeth. The orangutan, called Bimbo, was relaxing on a platform around 5m high in his enclosure when he broke out into a laugh. But his happy smile soon disappeared when another orangutan came over to see what was going on. Bimbo – the only male in the group of five apes at Leipzig Zoo, in Germany - appears to be laughing in much the same way as a human would. (Photo by Martina Radtke/Solent News)