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)

A person wearing a face mask holds a cat on Swanston Street after cases of the coronavirus were confirmed in Melbourne, Victoria, Australia, January 29, 2020. (Photo by Andrew Kelly/Reuters)

This 1950s photo provided by the Estate of Vivian Maier and John Maloof Collection shows Maier in a self-portrait as she looks into a storefront wearing a hat in New York. New research about Maier shows the enigmatic Chicago nanny was obsessive about honing her skills as a photographer starting in 1950. (Photo by Vivian Maier/Estate of Vivian Maier and John Maloof Collection via AP Photo)

Two attendees compete in the biggest vape cloud competition at the Vape Summit 3 in Las Vegas, Nevada May 2, 2015. According to new research provided to Reuters, youngsters say that performing tricks is one of the top two reasons they began using e-cigs. (Photo by David Becker/Reuters)

Police officers check documents of a man in central Moscow, Russia, Sunday, June 25, 2023. (Photo by Dmitri Lovetsky/AP Photo)

A rainstorm moves over the Atlantic Ocean after passing through Camden, Maine, at sunset, Tuesday, August 1, 2023. (Photo by Robert F. Bukaty/AP Photo)

Before sunrise there is a “Turneresque” sky over the abbey at the picturesque Wiltshire, England market town of Malmesbury on June 11, 2023. (Photo by Terry Mathews/Alamy Live News)

A woman poses for a friend next to blossoming trees in the A.V. Fomin Botanical Garden, in Kyiv, Ukraine, Wednesday, April 10, 2024. (Photo by Vadim Ghirda/AP Photo)