On the Night Walk on the North Side of Tortuguero, travelers will have the chance to experience the rainforest’s nocturnal wonders. One of the highlights of this tour is spotting glowing fungi, a fascinating bioluminescent species that illuminates the forest floor in the dark. Other possible wildlife sightings include: Red-eyed tree frogs – A classic symbol of Costa Rica’s wildlife. Tarantulas – Often found hiding in tree trunks and burrows. Sloths – Slowly making their way through the treetops. Scorpions – Some species glow under UV light. Snakes – Including tree boas and other nocturnal species.