Before the release of Fur 'n' Seek (when foxes were unattackable), the examine text for the fox was 'foxy'.
Before the release of the Fur 'n' Seek quest, there was only one fox wandering around north of Sinclair Mansion. After the quest was released, the number of foxes was increased and they were given a combat level of 57.
When killing a fox, it is known to have chances to drop a raw chicken. This is because of the chicken being a fox's main diet.