Elephants eat straw at a camp in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. Thailand celebrates World Elephant Day on August 12, an annual event held to raise awareness about elephant conservation. (Photo by Chaiwat Subprasom/Reuters)

Tourists ride elephants in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. (Photo by Chaiwat Subprasom/Reuters)

A mahout plays with an elephant at a camp in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. (Photo by Chaiwat Subprasom/Reuters)

A mahout sprays an elephant with water at a camp in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. (Photo by Chaiwat Subprasom/Reuters)

Mahouts and volunteers bathe their elephants in the Pasak river in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. (Photo by Chaiwat Subprasom/Reuters)

Straw covers the head of an elephant at a camp in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. (Photo by Chaiwat Subprasom/Reuters)

Mahouts and volunteers bathe their elephants in the Pasak river in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. (Photo by Chaiwat Subprasom/Reuters)

Students and their teacher play with elephants at a camp in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. (Photo by Chaiwat Subprasom/Reuters)

An elephant stretches its trunk out of an enclosure at a camp in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. (Photo by Chaiwat Subprasom/Reuters)

Students and their teacher play with an elephant at a camp in the ancient Thai capital Ayutthaya, north of Bangkok, Thailand, August 11, 2015. (Photo by Chaiwat Subprasom/Reuters)

An elephant attempts to intimidate visitors in the Kruger National Park situated 60 kilometres east of Nelspruit, November 24, 2009. (Photo by Rogan Ward/Reuters)

A mahout rides his elephant on the banks of the river Yamuna in New Delhi, March 17, 2015. (Photo by Adnan Abidi/Reuters)

Decorations on an elephant are seen during an elephant beauty contest at the Elephant Race event in Chitwan, about 170 km (106 miles) south of Kathmandu December 27, 2012. (Photo by Navesh Chitrakar/Reuters)

An orphaned elephant feeds from a bottle at the Daphne Sheldrick Wildlife Trust for Orphans within the Nairobi National Park, near Kenya's capital Nairobi April 21, 2012. The orphanage is operated by Daphne Sheldrick, wife of late famous naturalist David William Sheldrick. The orphaned elephants raised by the Trust are returned back to join the undomesticated elephant population in Tsavo National Park, where David was the founder Warden from 1948 to 1976, when they mature usually between eight to ten years old. (Photo by Thomas Mukoya/Reuters)

An Indian elephant calf sits in her enclosure at Chester zoo, northern England, January 24, 2011. (Photo by Phil Noble/Reuters)

A one and a half months old baby elephant stands close to its mother at Chitwan National Park in Chitwan, south of Kathmandu December 30, 2014. (Photo by Navesh Chitrakar/Reuters)

Elephants feed at a feast during the Elephant Festival event at Sauraha in Chitwan, south of Kathmandu December 27, 2014. (Photo by Navesh Chitrakar/Reuters)

An elephant pulls a teak log in a logging camp in Pinlebu township, Sagaing, northern Myanmar, in this picture taken March 6, 2014. (Photo by Soe Zeya Tun/Reuters)

A mahout washes his elephant ahead of the annual Perahera (street parade) of Rajamha viharaya temple, in Colombo September 5, 2012. (Photo by Dinuka Liyanawatte/Reuters)

An orphaned baby elephant walks through mud as tourists take pictures at the David Sheldrick Wildlife Trust Nursery within Nairobi National Park, near Kenya's capital Nairobi April 21, 2013. (Photo by Darrin Zammit Lupi/Reuters)

Bull elephant Maxi (L) gives his daughter Chandra (R) a playful shove with a tusk in the Zurich zoo July 15, 2002. (Photo by Andreas Meier/Reuters)

A mahout climbs his elephant as he heads towards the Chitwan National Park at Sauraha in Chitwan, about 170 km (106 miles) south of Kathmandu, December 28, 2012. (Photo by Navesh Chitrakar/Reuters)

An elephant walks towards tourists in Amboseli National park, Kenya, August 8, 2015. (Photo by Goran Tomasevic/Reuters)

An elephant walks through a swamp in Amboseli National park, Kenya, August 8, 2015. (Photo by Goran Tomasevic/Reuters)

An elephant walks out of a swamp in front of tourists in Amboseli National park, Kenya, August 8, 2015. (Photo by Goran Tomasevic/Reuters)

A mahout decorates his elephant using chalk while preparing for the Elephant Festival at Sauraha in Chitwan, south of Kathmandu, December 26, 2014. (Photo by Navesh Chitrakar/Reuters)

An elephant destroys a minibus after throwing its rider and going on a rampage during Sri Lanka's sixth annual elephant polo tournament in Galle February 15, 2007. Abey, a four-tonne eighteen-year-old elephant, threw off his mahout and American rider and went on a rampage destroying a vehicle before being subdued. (Photo by Buddhika Weerasinghe/Reuters)

The trunk of a newborn Asian elephant is seen next to his mother Farina at Pairi Daiza wildlife park, a zoo and botanical garden in Brugelette, Belgium, May 25, 2015. (Photo by Francois Lenoir/Reuters)

An Asian elephant dries off with some sand in his enclosure at the zoo in Karlsruhe July 7, 2011. (Photo by Alex Domanski/Reuters)

Two baby orphaned elephants touch trunks as they give themselves a dust-bath in the red earth after being fed milk from a bottle by a keeper, at an event to commemorate World Environment Day at the David Sheldrick Wildlife Trust Elephant Orphanage in Nairobi, Kenya Wednesday, June 5, 2013. (Photo by Ben Curtis/AP Photo)

An elephant rides a tri-cycle to promote a Bike for Mom event in Pattaya on August 12, 2015. The Bike for Mom campaign, a 43-kilometre ride through the Thai capital, will be held on August 16 to commemorate Thai Queen Sirikit's 83rd birthday. (Photo by Pornchai Kittiwongsakul/AFP Photo)

In this Monday, December 17, 2012 file photo, a herd of adult and baby elephants walks in the dawn light in Amboseli National Park, southern Kenya, as the highest mountain in Africa Mount Kilimanjaro in neighboring Tanzania is seen in the background. (Photo by Ben Curtis/AP Photo)

A mahout watches the Thai animation movie Kan Kluay with his elephant in Ayuthaya province, about 80km (49 miles) north of Bangkok June 5, 2006. The movie tells the story of a young Thai wild elephant who, while looking for his father, becomes the war elephant of the Thai King fighting against Burma and restored Thailand's ancient Ayuthaya empire that existed about 400 years ago. (Photo by Sukree Sukplang/Reuters)