Baloo

It's my understanding that the enormous ears of the basset hound serve an additional purpose (to hearing) in that as the hound sniffs, its ears will rub against the ground, freeing up scents.

My question: is this an example of
1) Evolution through Design (i.e. original breeders selected for hounds with longer ears for exactly what they are used for)
2) Evolution through natural selection (i.e. breeders selected for hounds best able to follow a scent; the big ears were the functional, but unplanned for, results).

Oh, and no, I'm not going anywhere with this - it's just a "chicken vs. egg" question I've always wondered about.

Albion

Depends what they were being bred for. If long ears help the dogs have better scenting capability, they'd probably be a side effect of breeding the most capable dogs. But if long ears were part of the breed standard for show dogs, there'd be breeders trying to breed for them independently. That sort of breeding for particular characteristics is part of the reason why some working-dog breeds like the border collie weren't part of the whole dog-show industry for a long time and why even now the standard for working breeds like labs is somewhat different for show dogs and working dogs. Breeding for the way the animal looks is not going to give you the best sort of working dog.

[ August 09, 2002: Message edited by: Albion ]</p>

One of the last sane

Basset Hounds have achondroplasia. This is a genetic disease which means the long bones don't develop normally. It happens in humans sometimes, you may have seen people with normal sized head and torso but very short legs and arms?
Same thing has occurred spontaneously in some breeds of dogs (I think it is a recessive gene)and been selected for. Dachshunds were originally achondroplastic Dobermann Pinschers but different colors and coats (longhaired etc) have been added. Bassets are the achondroplastic version of a French hound breed, and this was bred with Bloodhounds afterwards. So...their ears trail on the ground because they have pathologically short legs.
There is also an achondroplastic breed of cow somewhere in the British Isles, Ireland I think, which is another breed that arose from a spontaneous incident of achondroplasia but has been bred for because with their little short legs they can't jump over the stone walls that the people there use as fences. Their head and body are normal cow-sized.

[ August 09, 2002: Message edited by: One of last of the sane ]</p>