A rare dugong creature was found washed up on a beach in southern Thailand.

Officials from the local marine center arrived at the scene after fishermen found the dead animal in Trang province on September 5.

The 8.5ft-long female marine mammal had no visible injuries so they were baffled as to what could have caused its death.

Director Narong Khoneiad from the Jao Mai Beach national park said it may be the first dugong to die in the country this year.

He said: "This is the first dugong of the year that we found dead so far. We need to investigate the cause of death as soon as possible."

The team took the Dugong's body back to the marine centre to perform a post-mortem examination.

Marine chief Santi Nilawat was assisted by veterinarian Piyarat Khumraksa and his staff in checking the dead animal's internal organs.

They found a massive 700 grams tumour inside the marine creature's liver, suggesting that the animal died of natural causes.

Vet Piyarat said: "After a few hours of surgery, we found there was a large tumour inside the dugong's liver. It was a natural death."

In Thailand, the death rates of dugongs decreased in the past two years as the numbers of seagrass, which they fed on, have also increased.

Dugongs are classed as vulnerable on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species