The official word from the National Museum is that the colony of nearly 2 million bats that has lived under its roof for decades has simply moved on. The wire mesh constructed by museum workers to block the rafters and rid the museum of bad smells and excrement explains why they have moved.
The mesh has been fully in place for about two weeks. There has been no slaughter of the animals, stressed Bertrand Porte, who heads the museum’s restoration workshop.
“Museum staff have always had a great respect for the bats,” he said, adding that he has seen museum director Khun Samen admonish people trying to catch bats for their dinner.
But as Joe Walston, technical adviser for the Wildlife Conservation Society, points out, “They need large roost areas in order to survive.” Unlike other breeds of bats, the wrinkled-lipped museum bats cannot live in trees or under the roof of small houses, he said.
Since they feed on crop pests, fruit pests and mosquitoes, the disappearance of the bat colony may mean an increase in the insect population in Phnom Penh, Walston said. It also means no more excellent fertilizer made from their excrement, he said.
The debate over what to do about the bats at the National Museum has raged for years. A false roof paid for by the Australian government in the mid-1990s gave the bats some refuge and helped keep the excrement problem at bay. A plan to lure the bats to a new home was abandoned when the volunteers who suggested it left Cambodia.
In the meantime, fleas, lice and dried excrement have been falling on museum staff and visitors. In the dry season, the wind would blow excrement dust through doors and windows, Porte said. In the rainy season, the smell was unbearable.
“The rain would turn excrement into a juice as black as percolated coffee that would run along the walls,” Porte said. “When it fell on artwork, it would permeate stone and leave black marks that could not be removed.”
“It damaged artifacts,” said Prince Sisowath Panara Sirivuth, secretary of state for the Ministry of Culture and Fine Arts. “If we had not taken action, this would have created serious problems.” The government has no money for elaborate measures to remedy the situation, he said, and resorted to the wire mesh.
The Wildlife Conservation Society had been trying to raise funds to rebuild the museum roof, which also leaks in rainy weather. The society contacted the museum more than a year ago and suggested the construction of a concrete ceiling supported by metal beams, Porte said. The society had discussed the project with donors, according to Walston.
The installation of the wire mesh came as a surprise, Walston said. He theorized the museum staff did not believe the new roof project would ever materialize. Khun Samen is out of the country and could not be reached.
Only a few bats still take refuge just outside the museum. The smell is gone, and so are the lice and excrement dust, Porte said.
The bats used to have two major homes in Phnom Penh—the Olympic Stadium and the museum, Walston said. Renovation work at the stadium has already deprived them of one of those homes.
Walston said that without a good home, the bats will not be able to breed and will eventually die out. He says they are now scattered without no large concentration at any one site.
Their disappearance may mean an additional 6,000 tons of mosquitoes in Phnom Penh this year, according to Australian consultant Greg Richards, who studied the bat colony in the 1990s. Such a mosquito heap would fill the same space as 4,000 large family cars.
