An example of this is P'an Hu, the dog-man from Chinese folklore. In western culture, dogs don't evoke the same connotations as wolves. When dogs are spoken of, there just isn't that air of mystery and wildness that is associated with wolves. Perhaps it's because the term dog includes all domesticated canines and it's hardly surprising that the image of a chihuahua with head held high baying at the moon doesn't stir the same emotion as a similar image of the wolf.

What about the ursine counterparts - the werebear - of Native American culture? The bear is a mighty creature, bested only by a man with a gun (or equivalent weapon) or nature herself. Not as agile as the wolf, the bear doesn't really need to be; when was the last time a wolf was witnessed knocking down a large sapling? But then, for some odd reason, once transformed into a 'werewolf' the beast assumes strengths attributable to neither of its originating species.
Perhaps the reason the werebear doesn't make it big in western culture is because the name is a bit too close to Care-Bears. However, one must ask the obvious question there; what could be scarier than a CareWereBear - a creature with a supernaturally powerful caring nature. Certainly the thought of a bone-crushing hug would be enough to frighten off the most determined of enemies (or maybe that was CareWearBear - trousers that take care not to chafe the parts that make us growl).
If not a werebear, then I suppose there is less likelihood of a werepig being successful. Although reality would ensure it was an extremely frightening experience, the idea of being chased through woods by a seemingly unathletic, squealing, and grunting beast doesn't sound all that terrifying. Not only that, but unlike its ursine and canine counterparts, the werepig doesn't sound as if it would be all that natural at predatory techniques such as tree climbing - even with the aid of human genes.
It looks like were going to have to forego exotic imaginary creatures such as the werechidna, werebadger, or the weregiraffe and go with an animal that has a little more romantic value. So, be on the lookout for the wereleopard, wereagle, weretiger, or when looking for an ally instead of an enemy, look towards the werehorse.