From Star Trek: Theurgy Wiki

Hailing from the planet Denobula, Denobulans were a gregarious, inquisitive people who had been allies of Humanity since the 2130s. Though Denobula was not one of the founders of the Federation, the Denobulans joined soon after. Denobulans were a sociable people, with distinctive expressive features, who are used to living in close, communal conditions, and whose extended family groups were large and complex — a Denobulan may have had several spouses, each of whom may have several partners of their own, and dozens of children between them. Culturally, they were intellectually curious, perceptive, and interested in a wide range of philosophies, though their scholarly nature, large families, and gregarious nature meant that relatively few of them ventured far from their homeworld.