Confirmed

American Alligator

Reptile · Wild

Source: Spotted directly in an official GTA VI trailer or screenshot.
Worth Knowing: The CCTV-style trailer clip of one wandering into a convenience store is a real nod to a 2013 incident where a Florida alligator got close enough to a Walmart's automatic doors to let itself in. GTA Wiki also documents a POACH worker pulling one out of a backyard pool in Trailer 1, real prominence in the Grassrivers region, and a nod on Leonida's own in-game state seal - which, per the wiki, mirrors the real Seal of Florida's depiction of an alligator.

More Reptile Species

Green Iguana

Sea Turtle

Snake

Confirmed

Reptile · Wild

Source: Spotted directly in an official GTA VI trailer or screenshot.
Worth Knowing: The CCTV-style trailer clip of one wandering into a convenience store is a real nod to a 2013 incident where a Florida alligator got close enough to a Walmart's automatic doors to let itself in. GTA Wiki also documents a POACH worker pulling one out of a backyard pool in Trailer 1, real prominence in the Grassrivers region, and a nod on Leonida's own in-game state seal - which, per the wiki, mirrors the real Seal of Florida's depiction of an alligator.

Green Iguana

Sea Turtle

Snake