A sociable, long-lived species with large extended families, represented aboard Enterprise NX-01 by Doctor Phlox.
Denobulans are a humanoid people from the planet Denobula, known for a friendly, cheerful nature and a remarkable ability to keep going with very little sleep. Their biology is different from a human's in several ways, including a pattern in which they hibernate once a year, and their large families are a central part of their culture.
Denobulan society values sociability and personal ties, and their marriages often involve several spouses, each with an extensive family. Their culture is generally warm and liberal, and they take a keen interest in new experiences and people.
The best known Denobulan is Doctor Phlox, the chief medical officer on the Enterprise NX-01 under Captain Archer, who delights in learning about the cultures he visits and treats his patients with a calm and genial manner. Phlox often keeps unusual creatures in sickbay and has an unfailing enthusiasm for medical research. His time aboard shows how Starfleet's early crews were built through friendly cooperation between different species.