Why do border collies have a prefound lump on head?

Collies can tend to get fat deposites. They are fine. Doctors can get it out but it is a very exspensive surgery.

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I personally have noticed this feature in dogs with highly intelligent and sensitive temperaments (in any breed); not proven by science, but my own observation of many dogs and many years. I always try to buy a puppy with that little "bump"near the back of its head.