I'll never forget our first visit to Aransas. After photographing two fat & happy alligators (I presume they were happy, for alligators, anyway

) at the fenced pond across from the ranger station/interpretive center, we hiked the Heron Flats Trail and were soon "greeted" by the low, insistent and
startling growl of a large alligator located just out of our sight. After realizing the gator could see us, but we couldn't see it, we quickly walked down the trail to avoid "infringing" on its territory. Just as we'd cleared the alligator, a family of three javelina -- two adults and one baby -- made a rukus in the brush and crossed the trail just in front of us, before disappearing back into the brush. I still have a photo of two javelina and the hindquarters of the third -- he was too quick for my camera and reflexes!
We've only seen one whooper from within the park, proper, and it was way off in the flats viewed from the observation tower. We've had better luck observing the herons on one of the guided birding tours out of Rockport (which we're long overdue for doing again! hint, hint, Justin!