Mr. Ben, a pygmy slow loris, is administed anesthetic during one of Bristol Zoo's in-house veterinary clinic routine health check-up and teeth clean as part of the Zoo's standard animal husbandry and welfare procedure at Bristol Zoo on June 18, 2009 in Bristol, England. (Photo by Matt Cardy/Getty Images)

Talini (R), a 9-month old 160-pound polar bear cub, swims with her mother Barle at the Detroit Zoo's Artic Ring of Life exhibit August 25, 2005 in Royal Oak, Michigan. Talini's birth was the first polar bear birth at the Detroit Zoo in fifteen years. Her mother Barle was wild born and was rescued by the Detroit Zoo from a circus in Puerto Rico in 2002. (Photo by Bill Pugliano/Getty Images)

Titanoboa, meaning "titanic boa," is an extinct genus of snake that lived approximately 60–58 million years ago, during the Paleocene epoch, a 10-million-year period immediately following the dinosaur extinction event. The only known species is Titanoboa cerrejonensis, the largest, longest, and heaviest snake ever discovered, which supplanted the previous record holder, Gigantophis.

A full-scale model of the snake was unveiled at New York City's Grand Central station before the exhibit opens at the Smithsonian in Washington DC.

Joseph Szabo was a frustrated high-school teacher in need of inspiration – so he started photographing his students, and captured all the angst and excitement of being caught between childhood and adulthood. Here: “Priscilla”, 1969. (Photo by Joseph Szabo/Courtesy of Michael Hoppen Gallery/The Guardian)

Children feed a giraffe at Pairi Daiza wildlife park, a zoo and botanical garden in Brugelette, Belgium, May 25, 2015. (Photo by Francois Lenoir/Reuters)

A walruses at Hagenbeck Zoo in Hamburg, Germany on July, 7, 2015. (Photo by Werner Struss/Startraks action)

A tiger plays in water at a tiger zoo in Chaing Mai, Thailand on March 31, 2021. (Photo by Soe Zeya Tun/Reuters)

A keeper stands next to llamas during the Annual Stocktake at ZSL London Zoo in London, Britain February 7, 2018. (Photo by Tom Jacobs/Reuters)