A large bull walrus returns to the shores of Prins Karl Forland after diving and feeding on clams. (Photo by Paul Nicklen/National Geographic). Svalbard, Norway, 2011
Carlos Boozer #5 of the Chicago Bulls grabs a rebound next to David West #30 of the New Orleans Hornets at the United Center on March 7, 2011 in Chicago, Illinois. The Bulls defeated the Hornets 85-77.
A rider holds on as a bull tries to throw him during the Bull Ride Spectacular on the first day of the 2014 Deni Ute Muster at the Play on the Plains Festival grounds on October 3, 2014 in Deniliquin, Australia. (Photo by Mark Kolbe/Getty Images)
Bulls fight during the Maghesangranti festival at Talukachandani village in Nuwakot district near Kathmandu, Nepal January 15, 2016. The village organizes the bullfight during the Maghesangranti festival that commemorates the start of the holy month of Magh, ushering in the coming of warmer weather and longer days. (Photo by Navesh Chitrakar/Reuters)
The FFZero1 by Faraday Future is displayed at CES Unveiled, a media preview event for CES International Monday, January 4, 2016, in Las Vegas. The high performance electric concept car was unveiled during a news conference by Faraday Future. (Photo by Gregory Bull/AP Photo)
Pokot men carry a part of a carcass of a bull killed by a young man during an initiation ceremony in Baringo County, Kenya, January 20, 2016. Far from the bustling city of Nairobi, in an isolated corner of Kenya's Rift Valley, young men from the Pokot community spear a bull in a ceremony called Sapana that takes them into adulthood. (Photo by Siegfried Modola/Reuters)