“Suri tribes boys are collecting the blood of a cow in a calabash the vein of the animal was opened with a bow and an arrow. Like most pastoralists the Surma people are drinking fresh blood which is from the cow vein. Only some minutes after the wound at the vein is closed again the animals are back with their herd”. (Photo and caption by Anthony Pappone)

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.

Daredevil Christopher Gillette writhes around with a huge alligator he has saved from death. He works at a Florida sanctuary that rescues the wild beasts if they stroll into neighbourhoods where residents can legally kill them. To raise cash for the centre at Homestead, staff put on shows to feed and wrestle the alligators. Photographer John Chapa, 41, and girlfriend Adriana Canargo, 30, took these shots. Photo: Assistant photographer Adriana Canargo dives with a wild alligator. (Photo by John Chapa/Barcroft Media)

Meerkats are weighed and measured during the ZSL London Zoo 's annual weigh-in on August 22, 2012 in London, England. The height and mass of every animal in the zoo, of which there are over 16,000, needs to be recorded. The measurements are collated in the Zoological Information Management System, from which zoologists can use the data to compare information on thousands of endangered species. (Photo by Oli Scarff)

Steam enthusiasts demonstrate their engines at the Great Dorset Steam Fair, the biggest event of its kind in Europe on September 2, 2011 in Tarrant Hinton, near Blandford, England. Over 200,000 people are expected to attend the 600 acre event, which is in its 43rd year and includes displays and demonstrations of steam and vintage machinery over five days. (Photo by Matt Cardy/Getty Images)

Fabrice Monteiro travelled to the most polluted places in Africa and created terrifying characters who roamed their midst dressed in eerie debris. They are spirits, he says, on a mission to make humans change their ways. Informed by Africa’s environmental problems, Fabrice Monteiro’s photographs aim to highlight urgent ecological issues all over the world. His series “The Prophecy” is on show at Photo Basel 2017 until 18 June. (Photo by Fabrice Monteiro/Photo Basel 2017/Mariane Ibrahim Gallery/The Guardian)