I'm not positive but I believe you're thinking about some of the unnatural crosses being done for the pet trade that cannot reproduce? Because in the wild, some kinds
do interbreed- Mojave & Southern Pacific rattlesnakes, for example. But rumors* about things like a cross between a rattlesnake & a harmless gopher snake (*started
because gopher snakes, like many other harmless species, vibrate their tails when threatened & to those hysterically afraid of snakes, the tail vibrating in dry brush even
sounds like a rattlesnake sometimes) are totally NOT true, even though they've been circulating for years.
In Florida, it may well be that some of these are making a "new & improved" version to better survive conditions. Nature's always re-inventing the wheel...it's a pity that
such headlines are bound to cause panic in some people and escalate snake-killings.