Den här kommer direkt från boken:
And such bees! Bilbo had never seen anything like them.
"If one was to sting me," he thought, "I should swell up as big again as I am!"
They were bigger than hornets. The drones were bigger than your thumb, a good deal, and the bands of yellow on their deep black bodies shone like fiery gold.
"We are getting near," said Gandalf. "We are on the edge of his bee-pastures."
Av anledningen är Beorns djur noterade i boken att vara något speciella:
At any rate he is under no enchantment but his own. He lives in an oak-wood and has a great wooden house; and as a man he keeps cattle and horses which are nearly as marvellous as himself. They work for him and talk to him. He does not eat them; neither does he hunt or eat wild animals. He keeps hives and hives of great fierce bees, and lives most on cream and honey.
Det finns ingen annan anledning, och vi måste vara nöjda med förklaringen att Beorn är en magisk person ("ingen förtrollning utan sin egen") som håller speciella djur.