This never got answered by the "intended" (Just1More) but if I had to guess, it's partly the size...about 2' smaller as adults. And while your "black" rat snake is very
docile (as most of these are when properly worked with as hatchlings), a Trans Pecos has a different demeanor...more naturally laid-back & more nocturnal, & very
graceful (maybe stealthy is a better word?). Either one is a great pet though. Yours is more of an "extrovert"and yours will be at least 5' as an adult, whereas
I've never had a Trans Pecos exceed 4-4.5', a very manageable size perfectly housed in a 40 gal. breeder tank. If yours was a male, you'd be looking at 6' at least.
My male Florida rat snakes (same "family") are 7', while the females are about 5' (partly because they waste a lot of food/energy laying dozens of slug-eggs yearly.
So for those who like 'em bigger (longer), get a male. But in Trans Pecos, both genders stay about the same. All great pets, just some differences.![]()