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)

Hooded demonstrators vandalise a shop window in Mexico City, during the commemoration of the 50th anniversary of the 1968 Tlatelolco student massacre, on October 2, 2018. Fifty years ago, Mexican troops opened fire on student demonstrators, killing hundreds just days before Mexico City hosted the 1968 Olympics – one of the darkest episodes in a year of global turbulence. (Photo by Ronaldo Schemidt/AFP Photo)

Belgian priest Philippe Goosse (L) blesses Bloodhound dogs during a religious and blessing ceremony for animals, outside the Basilica of St Peter and Paul in Saint-Hubert, Belgium November 3, 2015. Hundreds of animals get blessed during the celebration of Saint Hubert, the patron saint of hunters who is also invoked for protection of dogs and horses, organisers said. (Photo by Yves Herman/Reuters)

Hot air balloons are displayed during an exhibition, in Caracas, Venezuela, 09 December 2022. The Government of Venezuela inaugurated an international transport exhibition to attract investment for a sector that has almost been paralyzed for the past five years but has begun to show signs of recovery this year. Venezuela has one of the most obsolete vehicle fleets in Latin America.. (Photo by Miguel Gutierrez/EPA/EFE)

A close up of a caracal lynx's face looking into a camera on January 2014 in Western Cape, South Africa. (Photo by Dale Morris/Barcroft Media)

Tatyana Abramova, 33, plays with her home fox Plombir at her countryside house outside Siberian city of Novosibirsk on September 12, 2020. The official start of the Soviet experiment to better understand the domestication of animals by humans began in 1959, and was initiated by geneticists Dmitri Beliaiev and Lioudmila Trout on a farm in Akademgorodok, the scientific center of excellence in Siberia. Their primary objective was to domesticate foxes, to understand how the ancestor of wolves, another canine, evolved into a loyal and loving dog. And understand what this domestication tells us about the genetic evolution of species. (Photo by Alexander Nemenov/AFP Photo)

Veterinarians and biologists from the Quito Zoo and the Andean Condor Foundation fit a tracking collar that juvenile Andean bear Tupak will wear for the next four years, prior to his reintroduction into the wild, after the bear's life was deemed in danger due to proximity to humans, in Quito, Ecuador on March 31, 2024. (Photo by Karen Toro/Reuters)

Actress Elaine C Smith grazes Siusan, the Highland cow, on Glasgow Green to mark being given the Freedom of the City of Glasgow, UK on Thursday, March 6, 2025. (Photo by Jane Barlow/PA Wire)