Another dog issue

[lewber]

We have a 4 1/2 year old male lab. He is very friendly and we don't have any issues with him interacting with people except in these cases- we like to take him places and if we take our pickup he rides in the bed hooked up to a tether that acts like a seatbelt. 
If the truck is parked, but he's still attached and someone comes up to the truck to pet him, he growls and sometimes lunges. He has never done this in any other situation. One person is someone he sees regularly on walks and in our home and he has been friendly to before. He's so friendly otherwise it catches us off guard when he does it in this situation, and now he has done it more than once. He has also done it once when he was in the backseat of my car with the windows down and someone tried to reach in to pet him. 
Is this because he's tethered and territorial about the truck bed and the car? Is it something we should worry about when he's in other situations?

Anything we can do in these situations? We've never had any issue with him on walks or in our house, even with new people and large parties. 

[MercyA]

Tethering a dog can absolutely contribute to aggression. A study done by some CDC physicians in the 90's found that tethered dogs are 2.8 times more likely to bite than those who are not.

 

It's hard to say whether your dog feels defensive because he can't escape or whether he is being protective of your property, but given his behavior, I wouldn't ever leave him tethered. I know that it is limiting, but it's not worth the risk, and you don't want him to get in the habit of behaving aggressively. 

 

You have my sympathy! At least your dog seems only to be aggressive in this particular situation. My last dog was unpredictably aggressive, and that was very difficult. 

Edited April 24, 2017 by MercyA

[wintermom]

Yes, I would definitely limit putting him in situations when you know he's been acting aggressively, and you have no control over what he might do to himself or a person passing.  

[Pawz4me]

It sounds like possession aggression, no doubt worsened by the tether. And very likely it's also exacerbated by the excitement of riding in a truck/car, going some place different, etc.

 

When you take him in the bed of the truck can you use a crate? Assuming the crate is secured that's probably the safest way to transport him (other than being inside the cab in a crate). That may be the only change you need to make to stop the problem in its tracks.

[Jyhwkmama]

You need to use a pet carrier. A tether in a pickup bed is not a safe way to transport a dog.