That's a cool sounding backyard, none that i've ever known is like that. well, and we are in an apt, so the "backyard" is the balcony.
BUT, scary. Bessie & Smili-- glad you gals are ok.
Yes, we know there's lotsa gators in Florida. When my person visited Florida as a kid, she saw ~20 of them in various places, including in the underpass of a freeway.