Quote:

this issue: apparently, these "hybrids" are fertile.


It is a myth that all hybrids are sterile. It was already a known fact that polar bears and brown bears produce fertile offspring. Many domesticated animals and pets are the result of crossbreeding among species. There are even 60 documented cases of mules that weren't, well, mules. Oddly, hinnies (male horse x female donkey) are more likely to be fertile than mules (male donkey x female horse).