Four dogs play the character of Wrolf. They all had their fur dyed so they looked identical, and each dog had its own talents. One was particularly good at barking, another at licking, one at running and one was good at just lying around.
It had been arranged for a real lion to be used in filming, and to be dyed black. However the insurance costs required for filming actors with a real lion were astronomical, so a digital lion was a much cheaper option.
In the series Sailor Moon, the character of Sailor Moon is revealed to be the Moon Princess. Two key characters in The Secret of Moonacre are called "Moon Princess". In the movie, Maria, one of the moon princesses, finds a moonacre hare and calls it Serena. The Japanese name of Sailor Moon, Usagi, is loosely translated as "rabbit". In the American version, her name is given as Serena. Hares and rabbits are from the same family.