Gunung Leuser National Park is a national park covering 7,927 km² in northern Sumatra, Indonesia, straddling the border of North Sumatra and Aceh provinces. The national park, named after Mount Leuser (3,381 m), protects a wide range of ecosystems. An orangutan sanctuary of Bukit Lawang is located inside the park. Together with Bukit Barisan Selatan and Kerinci Seblat national parks it forms a World Heritage Site, Tropical Rainforest Heritage of Sumatra.

Japan's ON-ART Corp's staff repaints the company's eight metre tall man-operated walking dinosaur robot “TRX03” at the company's studio in Tokorozawa, Japan, December 6, 2016. (Photo by Toru Hanai/Reuters)

A Saddle-billed Stork is seen in Amboseli National park, Kenya, February 10, 2016. (Photo by Goran Tomasevic/Reuters)

Volunteers transport an inflated sphere into a canoe to be lowered in MacArthur Park Lake during the installation of Portraits of Hope's exhibition “Spheres at MacArthur Park” in Los Angeles, California August 21, 2015. The installation will feature about 3,000 inflatable hand-painted spheres. (Photo by Mario Anzuoni/Reuters)

Executive producer Dave Alpert attends the season five premiere of “The Walking Dead” at AMC Universal Citywalk on Thursday, October 2, 2014, in Universal City, Calif. (Photo by John Shearer/Invision for AMC/AP Images)

A Dartmoor Hill pony foal runs on the moor on Dartmoor on May 17, 2011 in Princetown England. Although a tourist attraction, especially during the foaling season and often seen as part of the landscape of Dartmoor, many ponies face an uncertain future due to unsustainable breeding and their falling market values. The charity South West Equine Protection estimates that last year 1500 ponies were slaughtered – with many being sold for lion meat to nearby zoos. Along with other equine charities, they are calling for the removal of stallions from the moor to bring numbers down to sustainable levels. (Photo by Matt Cardy/Getty Images)

A humpback whale is seen at the beginning of whale watching season during a Manly Whale Watching tour on June 8, 2011 in Sydney, Australia. The first day of winter in New South Wales, June 1st, marks the start of the Humback and southern right whales migration from southern regions to the north to warmer waters. Whale watchers should expect tohave plenty to see with the whale population increasing each year. The migration north continues through July and with the whales returning between September and November. (Photo by Cameron Spencer/Getty Images)

Kenya Wildlife Service and Save The Elephants staff push an elephant as they undertake the collaring of ten elephants ranging near the Standard Gauge Railway to fit them with advanced satellite radio tracking collars in Tsavo National Park, Kenya March 15, 2016. (Photo by Goran Tomasevic/Reuters)