Hundreds of rare animals have been found frozen to death following an Air France flight from Madagascar to Switzerland.
Many of the creatures, which included exotic chameleons, frogs and hedgehogs, were due to be housed at a Zurich reptile centre and at the city zoo.
Reptile centre director Martin Schreiber arranged the February 7 flight with Air France, and even travelled to Madagascar to help pack the animals, but he was unable to travel back on the same flight and claims the airline failed to follow his precise instructions.
"I told Air France that the animals had to be kept in temperatures above 20 degrees centigrade and that they should not be left in the cold for more than three minutes," Schreiber said.
"But when I arrived in Zurich to collect the animals, they were freezing. Even after storing the containers for two hours in the animal room, which has a temperature of around 25°C, they had only warmed up to around 14 degrees."
Despite Schreiber's efforts to revive them, some 600 animals died - roughly a third of all the animals on board the plane.
Schreiber is now threatening to sue Air France "if only to make sure nothing like this happens again".
He said he had yet to receive any apology from the airline and had only been sent a brief email suggesting that the damage to the animals may have occurred during a three-and-a-half hour stopover at Paris Charles de Gaulle Airport.
Air France was more forthcoming with the media on Wednesday, sending out a statement to announce that an inquiry was already under way.
The airline adds that it would usually have sent the animals for routine veterinary checks during the stop in Paris, but did not on this occasion because "the customer specifically asked us to speed up the transportation and put the animals on the earliest flight to Zurich."
Air France received little support from its fellow operators on Wednesday, however, with Swiss airline spokesman Manfred Winkler expressing his amazement at the news.
"We at Swiss are involved in about 6,000 animal transportations a year," Winkler told swissinfo. "On our planes the temperature and oxygen levels in the hold are constantly monitored and we have never had an accident.
"What happened with Air France is really astonishing. Someone must have made a pretty serious mistake."
The director of Zurich zoo, Dr Alex Rübel, told swissinfo he had no intention to seek compensation from Air France, despite losing 34 animals on the flight.
"Our main priority is to discover exactly what went wrong and work together with the airline to ensure more professional behaviour in the future," Rübel said. "The animals coming to us were due to be part of the zoo's new rain forest biosphere, but fortunately none of those that died were especially endangered species."
The deaths of the animals, which made the front page of Switzerland's largest circulation tabloid "Blick", looks likely to reignite discussions over the need for animal transportation, with the animal rights group Pro Wildlife already calling on airlines to stop carrying rare or endangered species.
Rübel insists though that such proposals would actually damage conservation efforts.
"These transportations form the basis of species survival programmes throughout the developed world and these programmes are vital for countries whose conservation projects are less advanced.
"It doesn't make sense to talk of boycotting airlines, because the animals would still be transported by other means - and those other means are a lot slower and more stressful for the animals."
Unlike Martin Schreiber's reptile centre, Zurich zoo says it is willing to use Air France for transporting its animals in the future, although it will not be arranging any more flights from Madagascar until the circumstances surrounding this month's accident have been cleared up.
swissinfo, Mark Ledsom in Zurich
Around 600 rare animals, including exotic reptiles and hedgehogs, died of cold following an Air France flight from Madagascar to Switzerland.
The animals were destined for Zurich zoo and a reptile centre.
Air France is investigating the circumstances behind the animal deaths.
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