In the wild, Dumeril's monitors commonly feed on insects, snails, crabs, frogs and fish. In captivity, Dumeril’s monitors will accept these items as well as various shellfish and rodents.

Dumeril's monitors are terrestrial to semi-aquatic, and have been known to remain submerged for up to 75 minutes. They frequently soak, swim and even sleep in water. As captive animals, Dumeril's monitors should be supplied with a large water container for these activities. Dumeril's monitors are also accomplished burrowers and climbers. This means that captives should have access to branches for climbing and basking, as well as substrate in which they can dig.

Dumeril’s monitors require temperatures ranging between 82 and 90 degrees Fahrenheit, with a warmer basking spot (up to about 95 or 97 degrees Fahrenheit). Nighttime temperatures can be lowered to around 70 or 75 degrees Fahrenheit. A thermal gradient is recommended.