The carcass of a male dugong, believed to be 20 years old, was discovered on Laem Lookmai Beach in Hat Samran. The animal was about 2 metres 47 centimetres tall and weighed about 250 kilos.
No traces of attack or tussle with a fishing net were found on the body.
The carcass has been taken away by officials of the Marine and Coastal Resources Research Centre for autopsy.
Aram Yankaew, Hat Samran district chief, said a dugong carcass was found on the beach in Tase Cape on July 29. That was also of a male dugong, approximately 20 years old and 2-and-a-half metres tall, he said. He added that the autopsy showed the animal had died from sickness.
He believes the two dugongs may have been swept ashore from Libong Island due to strong monsoon tides. Dugong live on Libong Island because there is plenty of seagrass in the area, he said.