Kumbuka, a male silverback gorilla sits next to the keeper's chalk board in his enclosure at London Zoo, Thursday, January 2, 2014. Home to more than 850 different species, zoo keepers welcomed in the New Year armed with clipboards as they made a note of every single animal. The compulsory annual count is required as part of ZSL London Zoo's zoo license, and every creature, from the tiny leaf cutter ants to the huge silverback gorilla is duly noted and accounted for. (Photo by Kirsty Wigglesworth/AP Photo)

Couples take part in the “Love and Challenge Marathon” in Hanoi, Vietnam, 16 August 2015. Fifty couples, who are going to get married, participated in the event which is held the fifth time. This year, the winners of the marathon received a honeymoon trip to Malaysia. (Photo by Luong Thai Linh/EPA)

A runner competes in the Great Wall Marathon at the Huangyaguan Great Wall outside Beijing, China, May 18, 2019. (Photo by Thomas Peter/Reuters)

Pets get ready before running a mini-marathon for dogs in Bangkok, Thailand May 7, 2017. From tiny chihuahuas to 60 kg (130 lb) mastiffs, hundreds of dogs and their owners jogged through a Bangkok park on Sunday to raise money for charity. (Photo by Jorge Silva/Reuters)

“We've reached 40km.” – Participants run at the 40km mark of the 2025 Chosun Ilbo Chuncheon Marathon, held in Chuncheon, Gangwon Province, South Korea on the afternoon of the October 26, 2025. (Photo by Park Seong-won)

A runner in fancy dress attempts a record in the TCS London Marathon on Sunday, April 27, 2025. (Photo by John Sibley/Action Images via Reuters)

Young gorillas monkey around with zoo visitors, sticking their tongues out and pressing their faces against the glass, February 2025. Mobi, 1, and Gaia, 10 months, are half sisters and often push each other away at the glass to get the attention of their observers at the Prague Zoo. (Photo by Lucie Stepnickova/Solent News & Photo Agency)

Alexander Levine crosses the Verrazzano-Narrows Bridge during the marathon in New York on November 3, 2024. (Photo by Brendan Mcdermid/Reuters)