It is mostly nocturnal, roosting in caves and mines during the day and emerging shortly after sunset for five to seven hours of activity.

[4] Parnell's mustached bat is an insectivore, taking a variety of insects such as beetles, moths, flies, and dragonflies.

[5] Females gather in warm caves with other species, including the Cuban flower bat (Phyllonycteris poeyi), during the breeding season.

The pups only leave the safety of their birth cave to forage and hunt when their forearm length reaches adult size.

The bat uses the long CF portion to evaluate relative motion, and the terminal downward FM to determine target distance.

It is the only bat in the family Mormoopidae to have evolved Doppler-sensitive sonar due to the long CF call component.