biting and guarding especially with white and sharp teeth. pitbullrottweiler mask rottweiler tibetan mastiff Do you like to run or do exercise? Well I’ll tell you the best information about the fastest dog in the world. A Greyhound. The greyhounds bones are help to the greyhounds running. Would you like to know why? Well here is why. The back spine of a dog is connected with her tail, so if he/she broke her tail the spine would be broken, but the spine is important because the dog needs it to run. The spine moves up and down because when the legs and paws come together in the middle the spine goes up, but when the legs and paws spread out the spine goes down. spine goes upspine goes down In conclusion after what I’ve learned and have been taught, I found out things I never knew before like the Tibetan Mastiff and the greyhound. those are really cool things, but I hope you find your perfect pup. Good Luck!