Yes, they are fruit bats. The amazing story is they have never destroied the fruit plantations around this area so people won't harm them. On the day the late abbot of Wat Pho Bangkhla passed away, many of them falled to death on the ground and did not fly for food for a few days. Nowadays, the bat population is increased a lot because hunting is prohibited according to the wildlife preservation laws. The tour to this temple is now available by the air-cond.city bus (Euro II standard) every weekends at THB >250 (US$7.25). You will also see 100years market, "Klong Suan" (Picture set in my post) and other 8 temples. Tour would start at 07.00 a.m.from the Samutprakarn City Hall. (suberb of Bangkok where you could see the largest crocodile farm in the world and the ancient city: the replica of most important landmarks of Thailand and some real antique buildings, also the Erawan shrine: the hugh 3 headed elephant building where you could see many wonderful attractions inside.).
Thank you for all the great info..hope to travel to Thailand one day and I will pass your info on to friends going there this summer. Thanks. So interesting about the fruit bats as well. 
