Marines finish a 10 kilometer training hike carrying 55 pound (25 kg) packs during Marine Combat Training (MCT) on February 22, 2013 at Camp Lejeune, North Carolina. Since 1988 all non-infantry enlisted male Marines have been required to complete 29 days of basic combat skills training at MCT after graduating from boot camp. MCT has been required for all enlisted female Marines since 1997. About six percent of enlisted Marines are female. (Photo by Scott Olson/AFP Photo)

Daniel Cheong, a dog behaviorist and trainer, steps over a leash as he walks a pack of dogs in Arlington, Va. on November 13, 2018. (Photo by Ricky Carioti/The Washington Post)

Nutrias venture near the camera at the river Nidda in Frankfurt am Main, Germany, 15 June 2017. The rabbit sized animals are often confused with biebers by amateurs. (Photo by Boris Roessler/DPA)

A herd of elephants cross a road that passes through the flooded Kaziranga National Park in the northeastern state of Assam, India, July 12, 2017. (Photo by Anuwar Hazarika/Reuters)

A photo taken by a member of the County Durham and Darlington fire and rescue Service of a coach on fire on the A1 in County Durham, England on March 2, 2017. Passengers were evacuated safely before flames engulfed the vehicle. (Photo by County Durham and Darlington Fir/PA Wire)

A dog sits in a plastic tub filled with water in Taipei, Taiwan, 28 July 2020. Betel nut seller Mr Luo, the dog's owner, said he puts his dog, a 12-year-old mixed breed called Ah Dai (Stupid), in a plastic tub filled with water whenever the weather gets hot. Ah Dai enjoys the bath and can sit in the basin for hours, according to Mr Luo. Luo has a dozen pairs of glasses for Ah Dai, so the dog wears different glasses every day and many tourists take photos of Ah Dai. (Photo by David Chang/EPA/EFE)

People wear face masks as they ride an E-scooter in the Old Elbe Tunnel in Hamburg, Germany, Thursday, October 15, 2020. To avoid the spread of the coronavirus the use of a face mask in the 117-year-old tunnel under the Elbe river is mandatory. (Photo by Michael Probst/AP Photo)

Vietnamese dentist Tran Phuong Thao and her husband Tran Minh Hieu wearing protective masks, kiss at their wedding ceremony during the coronavirus disease (COVID-19) outbreak in Hanoi, Vietnam on January 28, 2021. (Photo by Kham via Reuters)