Could my Sheltie really do this?

Question
I have a one year old Sheltie named Marley. He is very sweet & has spent his entire life so far with two other dogs we have, both larger mutts. I also take him to dog training classes at Petsmart. Point is, he is well socialized & loves the dogs he lives with very much. We have a large property on a lake & we left the dogs run free because they stay close to home. However, we had a neighbor come over about a month ago. She said that Marley goes to her backyard & attacks her Jack Russel Terriers. I am very suprised by this. Marley is timid in class & even shy with the other dogs, even the small terrier. I just can't see him attacking another dog. Nevertheless I assured her that we would watch him more closey & we are putting a fence up so he cannot get in her yard.
This morning I awoke to the neighbor at the door. She said Marley & Lucy, one of our other dogs were in her yard again & Marley attacked her poodle. He bit her stomach so badly that they were taking her to the emergency vet & they didn't know if she was going to make it.
My question is, does this sound like Sheltie behavior? I cannot believe he would do such a thing. We have fox's & coyotes in the area too, so it seems more likely to me that her dogs get attacked by these things & maybe our dogs go in the yard to try to help the smaller dogs? I have no proof that he did or didn't do these attacks either way. He didn't have a drop of blood on him this morning though & no signs of a scuffle at all. It all seems a little fishy to me.

Thanks in advance for your help!
Katie Gibson
McHenry, IL

Answer
Katie,

My expert opinion is that it is EXTREMELY unlikely that a Sheltie will show that kind of aggression, ever.  Shelties are bred to be very passive except when defending the flock.  They will bark at anything, but tend to run when threatened back.  Most breeds including Shelties will demonstrate a consistent temperament and your experience with other dogs leads me to the conclusion that he can't do this.   Marley has been socialized with other dogs without problems so I would automatically eliminate him.

Exactly what evidence to prove it was Marley do they have?  Have they witnessed this?  If they have no evidence then they should be open to finding the truth rather than assuming they have the answer and forming a lynch mob mentality.

(For you to know, not share with neighbors because they will be unwilling to listen to anything you say) Of the breeds you have mentioned, Jack Russels are by far more aggressive and in fact can be dangerous to children.  They were bred to kill rats in barns by attacking and shaking them.  Shelties are bred to protect and guard, not attack.  The only reported case of a Sheltie attacking another dog I can find was one that defended a child against a pit bull.  The Sheltie did not survive the encounter but the child was unharmed.

I would leash Marley and keep my dogs inside until this is resolved.  We do not know what irrational thinking your neighbors have and may do.  That fence is an emergency project for your family.  Remember your neighbors are very stressed out about this and have focused on your dog, possibly to the point of having blinders on that there could be any other possibility.  

Based on your description I would feel confident that taking Marley over to their house on a leash (muzzled if possible) would be enlightening to them.  How does Marley react to their dogs?  How do their dogs react to him?  Is he aggressive or playful?  Do their dogs cower away or attack?
Carry a squirt bottle with you just in case you need it to settle things down and break things up, meaning the dogs not the neighbors...

Summary; the idea of a socialized one year old Sheltie being vicious is ludicrous.  However your neighbors will not listen to reason so if they are open to it bring Marley over muzzled and leashed but at the very least please do build the fence!

Dave