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)

A leopard attacks an Indian man as others climb a wall to get away from the animal in Lamba Pind area in Jalandhar on January 31, 2019. After a leopard was spotted in a house in Lamba Pind area of Jalandhar city, subsequent attempts to capture it led to the animal attacking at least six people, though none was injured seriously, local media said. (Photo by Shammi Mehra/AFP Photo)

In collaboration with the Pennsylvania Department of Transportation, Allegheny College art students repurpose used street signs as art materials to create the PennDOT Road Sign Sculpture Garden in Meadville, Pennsylvania, USA on August 19, 2017. (Photo by Brian Cahn/ZUMA Wire/Rex Features/Shutterstock)

A man walks his dog as the sun sets in a park in Frankfurt, Germany, Monday, September 18, 2017. Cool damp weather is set to continue in this part of Germany for the next few days with temperatures in the mid teens Celsius. (Photo by Michael Probst/AP Photo)

An injured supporter of Kenyan opposition leader Raila Odinga receives assistance in Nairobi, Kenya on November 17, 2017. Kenyan police have used tear gas and water cannons to disperse supporters of opposition leader Raila Odinga who are trying to gather near the country's main airport and Uhuru park to welcome him back from an overseas trip. (Photo by Baz Ratner/Reuters)

An army dog stands up as retiring soldiers salute their guard post before retirement in Suqian, Jiangsu province, China on November 29, 2017. (Photo by Reuters/China Stringer Network)

Armed female members of the militant Palestinian group Islamic Jihad carry Kalashnikov assault rifles as they take part in a rally to protest against US President Donald Trump's decision to recognise Jerusalem as the capital of Israel, in Gaza City on December 11, 2017. (Photo by Mohammed Abed/AFP Photo)

North Korean soldiers march during a military parade marking the 105th birth anniversary of the country's founding father Kim Il Sung in Pyongyang, North Korea, April 15, 2017. (Photo by Damir Sagolj/Reuters)