From 1764-1767, a creature that became known as the Beast of Gevaudan began terrorising southeastern France. The first sighting happened in a forest where a woman saw a wolf-like beast that was driven off by her cattle. Not long afterwards, people's bodies were being found torn apart, including a girl whose heart was torn out. Supposedly, people had shot at it with little effect to the Beast. Some hunters shot it repeatedly, after which it limped off. The killings resumed in a few days.
King Louis XV sent a group of soldiers were sent to kill the Beast. The soldiers thought they had killed it, but the killings continued after they left. Apparently, people even left entire villages out of fear of the Beast. Finally, in June 1767, the Beast was killed by Jean Chastel, who had fired 2 silver bullets into it (believing it was a werewolf). All in all, about 60 people were killed by the Beast of Gevaudan. The corpse of the Beast was taken throughout France, and then buried after it started to rot.
The Beast of Gevaudan definitely existed, though no one is sure just what it was. A Paris newspaper said that the Beast was bigger then a wolf, had red fur, and a black colored back. The paper also suggested that the Beast was a cross-breed of a wolf and a hyena. It has been suggested that it was a wolf, though such a killing spree is uncharacteristic of wolves (to say the least). There is also the more sensational idea that it was a werewolf, as believed by the peasents of the day. Unfortunately, we will probably never be sure what it was, as the body was never preserved and it is now over 200 years since the killings.
I'm not sure if this has any connection to the Beast of Gevaudan, but animals that looked like combinations of a wolf and hyena were sometimes seen in Montana and Idaho during the 19th century. There is a photograph of one that was killed (the body is no longer around); I have heard that it is similar to a species of prehistoric hyena-like dogs.