A photographer tested the concentration of several pairs of dogs as he captured their reactions to treat time in a series of shots. Christian Vieler, 47, of Waltrop, Germany, has been a professional dog photographer since 2016. He came up with the idea of snapping two dogs catching treats simultaneously. Here: Basset Hounds. (Photo by Vieler Photography/Caters News Agency)

Old Heidelberg, Dog with Pipe, 1905. (Photo by Detroit Publishing Company)

Fans attend the World Premiere Of Marvel Studios' “Captain America: Brave New World” at TCL Chinese Theatre on February 11, 2025 in Hollywood, California. (Photo by Frazer Harrison/WireImage)

A squirrel begs for food from a scooter driver in a park in Moscow on September 2, 2025. (Photo by Alexander Nemenov/AFP Photo)

A fox stands along a street in the Central London, Wednesday, March. 1, 2023. (Photo by Kin Cheung/AP Photo)

An Indian paramilitary trooper stands guard next to a mural along a street ahead of the G20 meeting in Srinagar on May 19, 2023. (Photo by Tauseef Mustafa/AFP Photo)

This photo taken on October 23, 2022 shows a soap bubble reflecting the Namsan Seoul Tower at Namsan Park in Seoul, South Korea. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

Meatball, a bulldog, poses in a tuxedo at the Tompkins Square Halloween Dog Parade on October 20, 2012 in New York City. Hundreds of dog owners festooned their pets for the annual event, the largest of its kind in the United States. (Photo by John Moore)