Authorities in Wallonia have opened a probe into the death of three sloths during a stopover at Liège airport, after the cargo jet on which they were being transported to Malaysia got stuck in a snowstorm.

The plane “was supposed to transit for two hours to refuel, but was not able to take off due to the weather conditions,” and was stuck in Liège on January 21 for 24 hours, said Wallonia Public Service spokesperson Nicolas Yernaux.

“For a reason that has yet to be determined and that is part of the investigation that we are conducting, the heating stopped or was stopped” on the plane, he added.

By the time Swissport — one of the biggest airport services companies in the world, which was in charge of organizing transport of the sloths — warned the Belgian authorities, three of the nine sloths that were on the plane had died.

Qatar Airways Cargo, which operated the flight, confirmed the three fatalities and said sorry. “Qatar Airways Cargo apologizes unreservedly for this loss, which is currently being fully investigated,” a Qatar Airways spokesman told POLITICO.

Contrary to previous reports from several Belgian outlets, the animals in question were two-toed sloths, not sloth bears, the Wallonian spokesperson said.

According to the Belgian authorities, the six remaining sloths were examined by vets, placed in heated rooms and rehydrated.

Once the sloths’ condition improved, the vets “assessed that the best [thing] was for them to reach their final destination, Kuala Lumpur, as quickly as possible,” the Wallonian spokesperson said.

‘Awful conditions’

Of the six existing species of sloth, only a couple have two toes, and none of them are currently under threat of extinction, according to the International Union for Conservation of Nature.

Although the transport of wild animals within the EU has to abide by the bloc’s rules — including stricter requirements for protected species — there is little oversight for exports to non-European countries, and member countries’ national agencies do not inspect planes in transit.

Several airlines, including Qatar Airways’ freight company, have committed to following a set of rules from the International Air Transport Association (IATA) regarding the transport of wild animals, which aim to “improve animal welfare and safety through appropriate quality and risk management,” according to IATA.

“We transport tens of thousands of animals each year without incident and we are deeply concerned by this tragic loss,” the Qatar Airways spokesman said.

But according to Nicholas Clark, from the pan-European animal advocacy group Eurogroup for Animals, wild animals continue to be transported around the world “in awful, poorly regulated conditions for a life in captivity.”

“We need to better regulate the trade in wildlife to put an end to these heartbreaking stories,” said Clark, who is the head of his organization’s wildlife program.

In a statement, Swissport said: “We are aware of the incident, but don’t have insights into the details of what happened as no handling was required by Swissport.”