Quais eram os cavalos de Madame Maxime que desenhavam a carruagem de Beauxbatons?

Que tipo de criatura eram os cavalos de Madame Maxime que atraíam a carruagem de Beauxbatons?

. . . they saw a gigantic, powderblue, horse-drawn carriage, the size of a large house, soaring toward them, pulled through the air by a dozen winged horses, all palominos, and each the size of an elephant. (GoF)

...

... the horses' hooves, larger than dinner plates, hit the ground.

...

"But ze 'orses -" "Our Care of Magical Creatures teacher will be delighted to take care of them," said Dumbledore, "the moment he has returned from dealing with a slight situation that has arisen with some of his other - er - charges." "Skrewts," Ron muttered to Harry, grinning.
"My steeds require - er - forceful 'andling," said Madame Maxime, looking as though she doubted whether any Care of Magical Creatures teacher at Hogwarts could be up to the job. "Zey are very strong. . . ."
"I assure you that Hagrid will be well up to the job," said Dumbledore, smiling. "Very well," said Madame Maxime, bowing slightly. "Will you please inform zis 'Agrid zat ze 'orses drink only single-malt whiskey?"

Quais eram exatamente aqueles cavalos do tamanho de um elefante com cascos maiores do que as placas de jantar? Uma criatura mágica conhecida? Cavalos regulares transfigurados?