Dog team races during a sled and skijoring competition outside Almaty, Kazakhstan February 18, 2018. REUTERS/Shamil Zhumatov

Siberian Husky dogs of the Royev Ruchey Park team pull a rig during a practice session for the Karadag Sled Dog Rally on the frozen Mana River, with the air temperature at about minus 21 degrees Celsius (minus 5.8 degrees Fahrenheit), in the Siberian Taiga area outside Krasnoyarsk, Russia February 6, 2018. REUTERS/Ilya Naymushin TPX IMAGES OF THE DAY

A Siberian Husky dog of the Royev Ruchey Park team is seen as it rests during a practice session for the Karadag Sled Dog Rally on the frozen Mana River, with the air temperature at about minus 21 degrees Celsius (minus 5.8 degrees Fahrenheit), in the Siberian Taiga area outside Krasnoyarsk, Russia February 6, 2018. REUTERS/Ilya Naymushin

A sled dog team pull a rig during the Aviemore Sled Dog Rally in Aviemore, Scotland, Britain January 27, 2018. REUTERS/Russell Cheyne

A sled dog team pull a rig during the Aviemore Sled Dog Rally in Aviemore, Scotland, Britain January 27, 2018. REUTERS/Russell Cheyne

A sled dog team pull a rig during the Aviemore Sled Dog Rally in Aviemore, Scotland, Britain January 27, 2018. REUTERS/Russell Cheyne

A sled dog team pull a rig during the Aviemore Sled Dog Rally in Aviemore, Scotland, Britain January 27, 2018. REUTERS/Russell Cheyne

A husky with different coloured eyes is seen at the Aviemore Sled Dog Rally in Aviemore, Scotland, Britain January 27, 2018. REUTERS/Russell Cheyne

A sled dog team pull a rig during the Aviemore Sled Dog Rally in Aviemore, Scotland, Britain. January 27, 2018. REUTERS/Russell Cheyne

A husky with different coloured eyes is seen at the Aviemore Sled Dog Rally in Aviemore, Scotland, Britain, January 27, 2018. REUTERS/Russell Cheyne

A husky with different coloured eyes is seen at the Aviemore Sled Dog Rally in Aviemore, Scotland, Britain January 27, 2018. REUTERS/Russell Cheyne

A husky with different coloured eyes is seen at the Aviemore Sled Dog Rally in Aviemore, Scotland, Britain, January 27, 2018. REUTERS/Russell Cheyne

Sled dogs are tethered before practice for the Aviemore Sled Dog Rally in Feshiebridge, Scotland, Britain January 22, 2018. REUTERS/Russell Cheyne

A Husky dog is tethered before practice for the Aviemore Sled Dog Rally in Feshiebridge, Scotland, Britain January 22, 2018. REUTERS/Russell Cheyne

A Husky dog is tethered before practice for the Aviemore Sled Dog Rally in Feshiebridge, Scotland, Britain January 22, 2018. REUTERS/Russell Cheyne

A Husky dog is tethered before practice for the Aviemore Sled Dog Rally in Feshiebridge, Scotland, Britain January 22, 2018. REUTERS/Russell Cheyne

A Husky dog team pull a rig during practice for the Aviemore Sled Dog Rally in Feshiebridge, Scotland, Britain January 22, 2018. REUTERS/Russell Cheyne

Sled dogs are tethered before practice for the Aviemore Sled Dog Rally in Feshiebridge, Scotland, Britain January 22, 2018. REUTERS/Russell Cheyne

A dog dressed as Santa Claus takes part in the annual city race in Skopje, Macedonia December 24, 2017.REUTERS/Ognen Teofilovski TPX IMAGES OF THE DAY

Dogs compete in a sled and skijoring race in the village of Kadnikovo outside Yekaterinburg, Russia, December 10, 2016. Picture taken December 10, 2016. REUTERS/Maxim Shemetov TPX IMAGES OF THE DAY

Dogs pull a musher in the 33rd Aviemore Sled Dog Rally in Aviemore, Scotland January 23, 2016. The Siberian Husky Club of Britain is holding its annual sled dog rally over the weekend. REUTERS/Russell Cheyne TPX IMAGES OF THE DAY

A dog sits on a field where migrants have crossed the border between Serbia and Macedonia, in the village of Miratovac, Serbia, January 17, 2016. REUTERS/Marko Djurica TPX IMAGES OF THE DAY

A musher greets his dog during a break in a stage of the Sedivackuv Long dog sled race in Destne v Orlickych horach January 22, 2015. Each year, racers from all over Europe arrive at the village of Destne in the Orlicke mountains in Czech Republic to take part in the race. Picture taken January 22, 2015. REUTERS/David W Cerny (CZECH REPUBLIC - Tags: ANIMALS SPORT TPX IMAGES OF THE DAY)

A dog rests in a cage during a sled dog European Championship in Venek November 22, 2014. REUTERS/Laszlo Balogh (HUNGARY - Tags: ANIMALS SOCIETY)

A musher races with his dogs during a sled dog European Championship in Venek November 22, 2014. REUTERS/Laszlo Balogh (HUNGARY - Tags: ANIMALS SOCIETY)

A Siberian Husky waits for the start of the "Full Wheels Drive 2014" open amateur dog sled and skijoring race near Yelovoye village, outside the Siberian city of Krasnoyarsk, February 9, 2014. About 100 dogs and their owners from various regions of Siberia including Altai, Novosibirsk, Kemerovo and Krasnoyarsk took part in the race. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS SOCIETY SPORT)

A man walks with his three huskies through a frosty fog along the bank of an island in the middle of the Yenisei River, with the air temperature at about minus 26 degrees Celsius (minus 14.8 degrees Fahrenheit) in Russia's Siberian city of Krasnoyarsk, February 2, 2014. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS ENVIRONMENT TPX IMAGES OF THE DAY)

A model presents a creation by Italian designer Giambattista Valli as part of his Fall-Winter 2013/2014 women's ready-to-wear fashion show for fashion house Moncler Gamme Rouge during Paris fashion week March 6, 2013. REUTERS/Gonzalo Fuentes (FRANCE - Tags: FASHION TPX IMAGES OF THE DAY)

A lead dog of musher Brent Sass races down 4th Avenue at the ceremonial start to the Iditarod dog sled race in downtown Anchorage, Alaska March 2, 2013.
REUTERS/Nathaniel Wilder (UNITED STATES - Tags: ANIMALS ENVIRONMENT SPORT)

Siberian husky Cookie of Germany's Juergen Stolz sleeps before the 6th international dog sledge race in Inzell January 26, 2013. REUTERS/Michaela Rehle (GERMANY - Tags: ENVIRONMENT SPORT ANIMALS)

Coletta Stolz, daugther of Germany's Juergen Stolz, current European Champion, cuddles up a Siberian husky before the start of the 6th international dog sledge race in Inzell January 26, 2013. REUTERS/Michaela Rehle (GERMANY - Tags: ENVIRONMENT SPORT ANIMALS)

Siberian huskies of Germany's Juergen Stolz look out of cages before the 6th international dog sledge race in Inzell January 26, 2013. REUTERS/Michaela Rehle (GERMANY - Tags: ENVIRONMENT SPORT ANIMALS)

Christian Hanf of Germany speeds with his six huskies during the 6th international dog sledge race in Inzell January 26, 2013. REUTERS/Michaela Rehle (GERMANY - Tags: ENVIRONMENT SPORT ANIMALS)

Huskies pant during a training session at Feshiebridge, in Aviemore, Scotland January 23, 2013. The Siberian Husky Club of Great Britain will hold its annual sled dog rally this weekend. REUTERS/David Moir (BRITAIN - Tags: ENVIRONMENT SOCIETY SPORT)

A musher races with his dogs during a sled dog competition in Dunaharaszti near Budapest, September 22, 2012. REUTERS/Laszlo Balogh (HUNGARY - Tags: ANIMALS SPORT SOCIETY)

A musher races with his dogs during a sled dog competition in Dunaharaszti near Budapest, September 22, 2012. REUTERS/Laszlo Balogh (HUNGARY - Tags: ANIMALS SPORT SOCIETY)

A musher feeds dogs during a break in a stage of the Sedivackuv Long dog sled race in Destne v Orlickych horach, January 26, 2012. Each year, racers from all over Europe arrive to the village of Destne in Orlicke mountains in Czech Republic to take part in this race series. REUTERS/Petr Josek (CZECH REPUBLIC - Tags: SOCIETY ANIMALS)

A musher pets his dog during a break in a stage of the Sedivackuv Long dog sled race in Destne v Orlickych horach, January 26, 2012. Each year, racers from all over Europe arrive to the village of Destne in Orlicke mountains in Czech Republic to take part in this race series. REUTERS/Petr Josek (CZECH REPUBLIC - Tags: SOCIETY ANIMALS)

A dog rests in his cage after a sled dog competition in Galyateto, 106km (66 miles) east of Budapest, January 22, 2012. REUTERS/Bernadett Szabo (HUNGARY - Tags: ANIMALS SOCIETY SPORT)

Dogs wait for the start of a sled dog competition in Galyateto, 106km (66 miles) east of Budapest, January 22, 2012. REUTERS/Bernadett Szabo (HUNGARY - Tags: ANIMALS SOCIETY SPORT)

A husky is keen to start running as preparations are made for the 29th annual Aviemore Husky Sled Dog Rally beside Loch Morlich, Aviemore, Scotland January 19, 2012. REUTERS/Russell Cheyne (BRITAIN - Tags: ANIMALS SOCIETY SPORT)

Dogs pant while their musher fixes a problem during the seventh stage of La Grande Odyssee sled dog race near Mont-Cenis January 15, 2012. The race crosses the Alps in France covering over 1000 km (621 miles) over 11 days. REUTERS/Denis Balibouse (FRANCE - Tags: SPORT SOCIETY ANIMALS)

A Siberian husky rests after a race at the fifth annual International Federation of Sleddog Sports (FIST) Chart European Championship in Smlednik November 19, 2011. 110 mushers with 600 dogs participated in the races which lasted over three days starting November 18. REUTERS/Srdjan Zivulovic (SLOVENIA - Tags: SOCIETY ANIMALS SPORT)

A musher and his sled dogs compete at the fifth annual International Federation of Sleddog Sports (FIST) Chart European Championship in Smlednik November 19, 2011. 110 mushers with 600 dogs participated in the races which lasted over three days starting November 18. REUTERS/Srdjan Zivulovic (SLOVENIA - Tags: ANIMALS SPORT SOCIETY)

Brennan Norden's dog team pulls him from the starting line of the ceremonial start of the Iditarod Trail Sled Dog Race in Anchorage, Alaska March 5, 2011. Alaska's Iditarod Trail Sled Dog Race started with an 11-mile (18-km) ceremonial run around Anchorage on Saturday, a prelude to a bleak trek over 1,100 miles (1,770 km) of wind-whipped trails in frigid weather. REUTERS/Al Grillo (UNITED STATES - Tags: SOCIETY ANIMALS)

A musher leaves a bivouac at the last stage of the Sedivackuv Long dog sled race in Destne January 29, 2011. Each year racers from all over Europe arrive to the village of Destne in Orlicke mountains in Czech Republic to take part in this race series. REUTERS/Petr Josek (CZECH REPUBLIC - Tags: SOCIETY ANIMALS)

A dog waits to be harnessed during practice for the Aviemore Sled Dog Rally on the shores of Loch Morlich, in Scotland January 20, 2011. The rally which involves over 1000 dogs and 200 mushers will take place on Saturday. REUTERS/Russell Cheyne (BRITAIN - Tags: ANIMALS ENVIRONMENT SOCIETY)

A dog waits to be harnessed during practice for the Aviemore Sled Dog Rally on the shores of Loch Morlich, in Scotland January 20, 2011. The rally which involves over 1000 dogs and 200 mushers will take place on Saturday. REUTERS/Russell Cheyne (BRITAIN - Tags: ANIMALS ENVIRONMENT SOCIETY)

Pete Jones the winner of the six dog team race in 2010, practices for the Aviemore Sled Dog Rally, on the shores of Loch Morlich January 20, 2011. The rally which involves over 1000 dogs and 200 mushers will take place on Saturday. REUTERS/Russell Cheyne (BRITAIN - Tags: ANIMALS ENVIRONMENT SOCIETY)

A dog reacts before the start of the tenth stage of the La Grande Odyssee sled dog race in Bessans January 17, 2011. The race crosses the Alps in France and Switzerland covering over 1000 km (621 miles) over 11 days. REUTERS/Denis Balibouse (FRANCE - Tags: SPORT SOCIETY ANIMALS)

Swiss musher Pierre-Antoine Heritier prepares food for his dogs at the Polar Base in the early morning before the second part of the eighth stage of the La Grande Odyssee sled dog race in Mont-Cenis January 16, 2011. The race crosses the Alps in France and Switzerland covering over 1000 km (621 miles) over 11 days. REUTERS/Denis Balibouse (FRANCE - Tags: SPORT SOCIETY ANIMALS)

A Siberian Husky is pictured during a race, with the air temperature at about -31 degrees Celsius (-23 degrees Fahrenheit), on the bank of the Mana river some 35 km (22 miles) southeast of Russia's Siberian city of Krasnoyarsk December 29, 2010. A group of people, celebrating the upcoming New Year holiday, took part in a sled dog race featuring Siberian Huskies. REUTERS/Ilya Naymushin (RUSSIA - Tags: ENVIRONMENT SOCIETY ANIMALS)

Siberian Huskies are pictured during a race, with the air temperature at about -31 degrees Celsius (-23 degrees Fahrenheit), on the bank of the Mana river some 35 km (22 miles) southeast of Russia's Siberian city of Krasnoyarsk December 29, 2010. A group of people, celebrating the upcoming New Year holiday, took part in a sled dog race featuring Siberian Husky dogs. REUTERS/Ilya Naymushin (RUSSIA - Tags: ENVIRONMENT SOCIETY ANIMALS)

Dogs rest near a box of frozen fish for sale from the Yenisei River in Russia's northern town of Igarka, about 1800 km (1118 miles) north of the Siberian city of Krasnoyarsk, April 14, 2010. Picture taken April 14, 2010. REUTERS/Ilya Naymushin (RUSSIA - Tags: ANIMALS FOOD)

A handler for Jessie Royer unloads dogs to feed them before the official start of the 2010 Iditarod Race in Willow, Alaska March 7, 2010. Seventy-one mushers and their powerful sled dog teams got a festive send-off in downtown Anchorage on Saturday for a 10-mile (16-km) ceremonial run that launched the fabled Iditarod Trail Sled Dog Race. REUTERS/Nathaniel Wilder (UNITED STATES - Tags: SPORT SOCIETY ANIMALS)

One of Jane Faulkner's dogs rests in its box before the ceremonial start of the Iditarod Trail Sled Dog Race in Anchorage, Alaska March 6, 2010. Seventy-one mushers and their powerful sled dog teams got a festive send-off in downtown Anchorage on Saturday for a 10-mile (16-km) ceremonial run that launched the fabled Iditarod Trail Sled Dog Race. REUTERS/Nathaniel Wilder (UNITED STATES - Tags: SPORT ANIMALS IMAGES OF THE DAY)

Dogs play before competing in the Arden Grange and Siberian Husky Club of Great Britain Aviemore Sled Dog Rally 2010, in Aviemore, Scotland January 23, 2010. Over 1000 sled dogs and 200 mushers took part in the rally, which for the first time in 15 years was able to be run on snow. REUTERS/Russell Cheyne (BRITAIN - Tags: ANIMALS SPORT IMAGES OF THE DAY ENVIRONMENT)

A sled dog waits in the snow before this weekend's sled dog Rally in Aviemore, Scotland January 21, 2010. Organised by the Siberian Husky Club of Great Britain the rally is run on tracks around Loch Morlich in the shadow of the Cairngorms. REUTERS/Russell Cheyne (BRITAIN - Tags: ANIMALS ENVIRONMENT)

Sled dogs wait in the snow on a practise day before this weekend's Sled Dog Rally in Aviemore, Scotland January 21, 2010. Organised by the Siberian Husky Club of Great Britain the rally is run on tracks around Loch Morlich in the shadow of the Cairngorms. REUTERS/Russell Cheyne (BRITAIN - Tags: ENVIRONMENT SOCIETY SPORT)