Our bloodhound was picked up/stolen a few weeks ago. I think in the next few months I will be trying to start another one. Our other dog is broken hearted without a companion. He was a great tracking dog, although I didn't pick him out, he was gifted to us and was the last one in the litter. I think we just got dumb lucky on him.
I have always had female dogs. When I duck/goose hunted and had labs, I liked the females better. For trackers, I still prefer females... but... unless they're "fixed" when they are in heat, they are pretty much useless as a tracker... my experience (and others have told me the same thing before I ever tried it) is that they can't smell squat when in heat... and I found it to be true... So if you have a female that routinely comes into season right during hunting season, you lose her services for about 3 weeks...or get her "fixed".
Given two identically talented dogs, I'll take the male - simply because there's no heat cycle and no chance for a pregnancy during the season.
As Blake said, it's all about the particular dog and I wouldn't hesitate to pick a female. I'd pick based on the indications of drive and intelligence, regardless of gender. Just have a few more things to watch with a female than a male.
My friend has a male that is not fixed and he is one heck of a tracking dog. I would guess you choose the gender for other reasons. That being said both my dogs are female but that is just how it worked out. Just my thought based on my very limited exposure and experience.
Comment