The only thing that I have had a problem with in the past are the darn porcupines. Last week there were 2 of them on the lawn, and they were fighting each other. My old dog had killed three of them in his lifetime before he realized that the pain wasn't worth the effort, and that was about 18 years ago. Lucky for me, none of my dogs have tangled with them since, although my almost 15 year old Weimaraner got dangerously close to one just a week before he passed away, three weeks ago. I don't think that he had ever seen one before in his life, and I believe that he was just being curious. Luckily, I spotted it as he started walking up on it, and I was able to grab his collar and keep him from getting any closer. If he wasn't so frail and slow moving, I probably wouldn't have been able to intercede in time.