I recently finished a 30 day trip to the Yucatan peninsula in Mexico. We did a lot of exploring of Mayan temple sites including one called Calakmul. This particular temple site is still very much surrounded by the jungle. There is only one road that leads in to Calakmul from the main highway, and it takes an hour to drive in to reach it once you start in. Anyways, there's a lot of wild life there: Howler monkeys, Spider monkeys, Tucans, and lots of bats. While we were in this jungle area, we made a trip to see a cave that is home to what has to be millions of bats. During the evening, which is their active feeding time, we watched as what started out as a trickle of some bats turned into a huge swirling swarm of what looked like a tornado of bats rising into the air as they exited the cave. This went on for an awesome half hour!
Anyways, I brought along a small sketch book and did a couple sketches of some bats. I did these while we were traveling on a bus from Tulum to Valladolid. They're a little goofy and certainly not accurate, but they were fun to do.