DENOBULANS

Planet of Origin: Denobula, the only planet orbiting  the star Denobula Triaxa AKA Iota Bootis, some 95 light years from Earth, in the Milky Way galaxy.
Denobulans are near-human looking humanoids with prominent facial ridges running down either side of the forehead to the cheeks, an enlarged brow ridge under a high receded hairline, a vertical crevice in the center of the forehead, and a ridged chin. They also have ridges on their back, along the spine. Their toenails are  dark brown and yellow striped, and they grow so rapidly that they need to be groomed once a week. Denobulans also had very long tongues, and they used tongue scrapers. Denobulan males had a line of hair down the middle of their chest, up to their throat. . They  have the ability to enlarge their faces when they feel threatened.  and they can change their eye color depending on their moods. . They  normally require  very little sleep, but do hibernate for five to six days each year. However, at a minimum, two days are sufficient. If a Denobulan is awakened prematurely, the results can be somewhat unpredictable; hibernating Denobulans, if woken, appeared extremely disoriented and confused, with oddly-pitched voices, and had difficulty maintaining normal motor skills and cognitive functions. Denobulans have  highly-efficient natural climbing abilities similar to those of Earth lizards, being capable of scaling vertical rock faces at a rapid speed with no equipment whatsoever, appearing to scuttle up the rock face without needing to find handholds and possess particularly powerful immune systems. Their exact life expectancy  is not known, but indications suggest that lifespans are extremely long.

On their homeworld,  the twelve billion Denobulan inhabitants all share one continent, resulting in  Denobulan culture having come to embrace close, communal lifestyles.  Denobulan medical ethics considers  a patient's will to be absolutely binding, including his denial to be cured or live.  Denobulans are typically polyamorous, where a man typically has three wives, who each has three husbands lcreating extremely large extended families. In addition, marriages are not exclusive, and married Denobulans can be intimate with anyone they chose. The females emit powerful pheromones during their mating season. Male Denobulans often became combative during this time, and mating can require medical supervision. Denobulans typically preferr to be among large groups and find solitude uncomfortable. However, Denobulans, at least males, are uncomfortable being touched by persons they are not intimate with and are more sexually inhibited than the females of their species.  Although Denobulans don't keep pets, they tend to address or greet animals they meet by imitating their sounds, even insects. 

Since the 20th century, the Denobulans practiced genetic engineering, with generally positive results and, by the 22nd century, the Denobulans had experimented with nanotechnology.  

The Denobulans believed they were the only intelligent species in the galaxy until the B'Saari made first contact.  Denobulans fought several wars against the Antaran species. The last one was during the late 19th century. Denobulan battle tactics killed twenty million Antarans. Both species demonized each other). As of the 22nd century, there were still some Denobulans that hated Antarans, although most had outgrown the hatred. . The Denobulans first met the Human race sometime prior to the 2130s. By the 2130s, Denobulans and Humans had built the joint research station Cold Station 12. When the Vulcans formed the Interspecies Medical Exchange, Denobulans were involved and contributed medical personnel. . In 2155, a Denobulan ambassador was sent to Earth to join in talks of forming a Coalition of Planets.

Source: Star Trek Universe,mainly Memory Alpha entry,. and pertinent episodes:
ENT: "Bounty", "A Night in Sickbay", ENT: "Home",  ENT: "Acquisition", ENT: "Two Days and Two Nights", "Fight or Flight", "Similitude", ENT: "The Breach", ENT: "Doctor's Orders", ENT: "Broken Bow", "The Expanse", ENT: "Dear Doctor", "Bounty", ENT: "Borderland", ENT: "Future Tense", ENT: "Demons", ENT: "Cold Station 12,