After going on the Dugong spotting tour in Koh Libong, I had an opportunity to talk to one of the tour guides from Trang who had reasonable facility with English. When I told him that we had sighted four individual dugongs, he said that we were very lucky as from his experience, only 10% of such tours are successful in seeing a dugong. When I asked about the social behavior of the dugongs, he told me that dugongs usually travel in a herd of up to 8 individuals.
Doing some further investigation on my own, I learned that the dugong herd typically consists of females and their calves; the males - for the most part - are solitary, only getting together with the females to mate. Furthermore, during the day the dugongs stay (resting quietly) in the deep sea coming to the shallow coastal areas, inlets and mangroves at night to feed eat on sea grass.
That could explain, why there are so few dugong sightings on these day tours as the herds are active mostly at night. I surmise that the individuals that we saw were solitary males patrolling their territory, but who I am to know!
As sort of a gag, I produced an impromptu video where I am seen swimming in the open seas impersonating a female dugong, in the hope of attracting a male dugong. Bret, the young and affable Canadian, provided the humorous narration