Mariana fruit bats are found in Guam and CNMI, and move from island to island. In northern Guam, bats forage and roost mainly in native limestone forest. Coconut groves and strand vegetation are other plant communities used occasionally for feeding and roosting. In southern Guam, a few fruit bats still inhabit ravine forests. Farms, savannas, and mangroves are habitats that receive little or no use at present but may have been used commonly in the past when bats were more abundant and widespread on the island.
Bats gradually depart colonies for several hours after sunset to forage.
The fruit bat feeds on a wide variety of plant material but primarily on fruits. It appears that the favored foods include the fruits of breadfruit, papaya, fadang, figs, kafu, and talisai and the flowers of kapok, coconut, and gaogao. Recent studies have indicated that the bats move from one island to another, linking these colonies as a single population. Both species of fruit bat probably once occurred throughout Guam in forested areas that formerly occupied most of the island. In 1958, a maximum of 3,000 bats were believed to be on Guam.