Cecil I would call that "genetic vigor" and it does occur (big vs. little people , High IQ , etc). Interesting is the comment on inbreeding depression - to many bad traits pop up and its corollary in hybrids - outbreeding depression - where the bad traits tend to pop up in offspring of hybrids (F2s F3s and FXs ).

Bruce what happened to the mini-tailed BG ? \:o - \:D - ;\)

Cecil do yours have that same genetic vigor ?