In the picture you can see two baby crocodiles.
When traveling to Tortuguero you should pack light. If you are traveling on a package deal, you may leave your luggage in your place in San Jose, and bring a small bag to Tortuguero.
You should bring T-shirts, two pairs of boots (you can rent rubber boots in Tortuguero if you do not have them), a couple of pairs of long trousers, and rain gear. Tortuguero is among the wettest regions in Costa Rica. Even during the dry season, showers are common.