You may know that Napoleon Dynamite declared the Liger — the cross between a male lion and a female tiger — “pretty much” his favorite animal.
What you may not know is that ligers are big:
Ligers grow much larger than tigers or lions and it is believed this is because female lions transmit a growth-inhibiting gene to their descendants to balance the growth-promoting gene transmitted by male lions (this gene is due to competitive mating strategies in lions). A male lion needs to be large to successfully defend the pride from other roaming male lions and pass on his genes; also, in prides with multiple male adult lions, a male’s cubs need to be bigger than the competing males for the best chance of survival. Thus, his genes favor larger offspring. A lioness, however, will have up to 5 cubs, and a cub is typically one of many being cared for in a pride with many other lions. As such, it has a relatively high survival rate, and need not be huge as it will not need to look after itself very quickly. Smaller cubs are more easily cared for and fed and are less strain on the pride; hence, the inhibiting gene developed.Male tigers do not compete for status and mates in the way lions do; a tigress only mates with one tiger when in season, so a tiger does not have the same genetic predisposition to produce large competing offspring. Also, a tigress typically has fewer cubs, and those have a much lower survival rate due to the tiger’s solitary nature, so being large and growing quickly are an advantage; there is no need for a growth inhibitor. Being the offspring of a male lion and female tiger, the liger inherits the growth-promoting gene unfettered by a growth-inhibiting gene and typically grows larger than either animal; this is called growth dysplasia.