A Somali police officer arrests a suspected rebel member of the al Qaeda-affiliated al Shabaab among beach goers in Mogadishu. Al Shabaab claimed responsibility for today's pre-dawn attack on a Kenyan university campus near the Somali border. The following gallery examines who is al Shabaab. Here: Somali police officer (R) arrests a suspected rebel member (L) of the Al Qaeda-affiliated al Shabaab among beach goers at the Lido beach north of Somalia's capital Mogadishu March 23, 2012. (Photo by Feisal Omar/Reuters)

A man dressed as Santa Claus sits at a bus stop before an annual race in Belgrade, Serbia December 27, 2015. (Photo by Marko Djurica/Reuters)

A woman affected by tear gas is assisted during a May Day protest against austerity measures, in San Juan, Puerto Rico May 1, 2018. (Photo by Alvin Baez/Reuters)

A chicken gingerly crosses the double yellow line of a country road near Roseburg in western Oregon, USA on July 16, 2018. (Photo by Robin Loznak/ZUMA Wire/Alamy Live News)

Russian Emergency Situations employees help a girl to bath in the icy water on Epiphany at the Church of the Holy Trinity in Ostankino near TV Tower in Moscow, Russia, Friday, January 18, 2019. Across Russia, the devout and the daring are observing the Orthodox Christian feast day of Epiphany by immersing themselves in frigid water through holes cut through the ice of lakes and rivers. Epiphany celebrates the revelation of Jesus Christ as the incarnation of God through his baptism in the River Jordan. (Photo by Alexander Zemlianichenko/AP Photo)

Participants wearing Zentai costumes, or skin-tight bodysuits from head to toe, take part in a march down the shopping district of Orchard Road during Zentai Art Festival in Singapore May 23, 2015. Close to 50 participants strutted down the busy shopping district during the Zentai art festival which is jointly organized by the Japanese embassy. The festival includes performances and discussions on Zentai from May 22 to from June 5. (Photo by Edgar Su/Reuters)

A male red deer with antlers covered in bracken, walks through undergrowth in Richmond Park in south west London, October 3, 2014. Over 600 red and fallow deer roam in the largest of London's Royal Parks, and have their numbers managed in an annual cull each November and February. (Photo by Toby Melville/Reuters)

Western lowland gorilla Kijivu holds her newborn baby at the Prague Zoo in the Czech Republic. (Photo by Isifa/Getty Images)