The week in wildlife – in pictures

A capped heron is seen at the Marañón river in Peru's Pacaya Samiria national reserve in the Amazon jungle. The reserve, measuring close to 2.08m hectares in area, is the biggest national reserve in Peru, containing 85 natural lakes which are home to 250 species of fish as well as both pink and grey freshwater dolphins Photograph: Pilar Olivares/REUTERS

Thomson's gazelles (Gazella thomsonii) peer at a camera trap set up by ecology student Blair Roberts at a wildlife-rich region in Kenya Photograph: Blair Roberts/ Rex Features

A European tree frog (Hyla arborea) in a garden in the eastern German town of Schönebeck Photograph: Peter Forster/AFP/Getty Images

Rob Cuss's image, Seal Sunrays, won first place in the Ambience category of Splash-In, Lundy Island’s annual underwater photography competition Photograph: Rob Cuss/lundyisland.co.uk

A bison and its calf on the grasslands of the El Uno ecological reserve in Janos, Mexico. Environmental authorities of the US and Mexico are joining forces to reintroduce the American bison – which almost became extinct in the 19th century – to the grasslands of northern Chihuahua state Photograph: Stringer/Reuters

A dragonfly lands on a stalk of wheat ready for harvest at sunset on the Canadian prairies near Vulcan, Alberta Photograph: Todd Korol/Reuters

A feral hog in a holding pen in New York state. Wildlife officials are devising a strategy to stop wild hogs from proliferating to the point where they are impossible to eradicate. In southern states, roaming droves have devastated crops and wildlife habitats with their rooting, wallowing and voracious foraging Photograph: Mike Groll/AP

A one-month-old baby Asiatic elephant is taken to safety by a forest official after it was abandoned by the herd in Sokordo village, on the outskirts of Guwahati city, north-east India Photograph: STR/EPA

An environmental activist releases a young black-tip shark into the sea as part of an operation organised by conservation group Dive Tribe off the coast of the southern Thai sea resort of Pattaya. On average an estimated 22,000 tonnes of sharks are caught annually off Thailand for their fins - a delicacy in Chinese cuisine Photograph: Christophe Archambault/AFP/Getty Images

Egrets look for food in the Xinkai River estuary in north China's Hebei province. As the season changes, migratory birds begin to arrive at the coastal wetland. Each year, hundreds of thousands of migratory birds stop here Photograph: Yang Shiyao/Corbis

A lizard nibbles at a discarded pastry during the 68th Venice film festival Photograph: Gareth Cattermole/Getty Images

A fur seal crosses a road in bushland, several kilometres inland from the Southern Ocean in Naringal, Victoria, Australia. The animal made its way into the small town by swimming up the Hopkins River and Brucknell Creek Photograph: Angela Milne/Fairfax Media/Getty Images

Caramello the koala meets members of the public at Wynyard park, Sydney. Caramello was among a number of animals on show to mark national threatened species day on 7 September, when zoos and aquariums across Australia united to raise awareness of endangered species Photograph: John Grainger/Rex Features

Smoke billows behind scorched trees about eight miles south of Tehachapi, California. The fires were ignited by a small plane crash that destroyed 27 homes and burned more than 14,800 acres Photograph: Felix Adamo/Corbis

Residents examine a 21-foot (6.4m) saltwater crocodile suspected of attacking several people. It was caught in Nueva Era in Bunawan town, southern Philippines and weighs 600kg - the largest crocodile caught in the country to date Photograph: Stringer/Reuters