I don't know about how snakes in Austin but there are some critters you don't want a kid to play with.
http://www.poisoncontrol.org/docs/toxic_bites.pdf I when in the Army at Fort Hood north of Austin there were rattlesnakes.
We live in Georgia and have had black widow spiders and saw my second scorpion last week. My daughter picks up dead bees and has ant bites on her body because she's fascinated with bugs.