In case you are going camping at Guadalupe River State Park this weekend you might want to look into the night time hike over at the adjacent Honey Creek Natural Area.  They will be featuring a guided hike hosted by a naturalist who will be able to tell you lots and lots about the critters and plants that live out there.  Should be fun and interesting.  http://www.tpwd.state.tx.us/calendar/honey-creek-at-night-1