Caligo eurilochus (forest giant owl) occurs from Mexico and Central America through tropical South America to the Amazon Basin. The adult is a very large butterfly whose closed hindwing bears a prominent ringed eyespot. It is most active in the low light of early morning and late afternoon, spending much of the day resting with its cryptic brown wing undersides exposed.

The elongated caterpillar is brown with darker longitudinal markings and a forked tail, a form that blends with dry plant material. Larvae feed on bananas, heliconias, and related monocots and can consume substantial foliage when numerous. Adults use fermenting fruit and plant sap rather than relying only on flower nectar. The species is commonly exhibited in butterfly conservatories outside its native range, but its wild populations are tropical American. Photographed in Ecuador.