Endemic subspecies
Scientific records of Formosan golden bats go back more than 150 years, to observations made in 1862 by the British consul in Taiwan, Robert Swinhoe, who was also a naturalist.
However, because specimen collections were incomplete, Formosan golden bats were regarded as a widespread species and received little attention until researchers during the period of Japanese administration compared them with other bats. They identified them as an endemic subspecies, Myotis formosus watasei. But despite this revelation, further study continued only intermittently.
The old Xu Family House in Yunlin County seems to have become a center of attraction for golden bats in recent years. In 1995, the place even attracted a group of Japanese scholars who came to study the bats.
After golden bats were found around Tainan and Chiayi, two scholars specializing in bat research—Professor Lee Ling-ling of the Institute of Ecology and Evolutionary Biology, National Taiwan University, and Professor Lin Liang-kong of the Department of Life Science, Tunghai University—have both found that Formosan golden bats are in fact different from Myotis formosus watasei. The nose and wings have dark spots, the fur is a lighter color, and their molar order is also different. After DNA comparison, the researchers were confident in assigning the Formosan golden bats to another subspecies, also endemic to Taiwan: Myotis formosus flavus.
Lin Liang-kong notes that currently, Taiwan has 30-plus species of bat. Most of them live their lives in caves or bushes to avoid predators or interference, and a small number of species such as Japanese house bats that sometimes inhabit urban areas tend to hide in dark places, so they aren’t often seen. In fact to see them hanging on eaves or trees like Formosan golden bats, which have no fear of sunlight, would be extremely rare.
Formosan golden bats come to the plains in early April each year. With a body length of about five to six centimeters, they often snuggle up against each other to maintain body warmth, and can be seen suspended from house eaves or broad-leaved trees such as the magnolia or Cuban bast.
Female bats generally deliver their babies between May and July, and hang upside down to breastfeed them in the outer edges of tree foliage where a little sunlight can filter through. After just one month, the young bats are able to follow the adults as they fly off in August and September. They’ve usually disappeared completely by the end of October.
But it’s a mystery where the golden bats go. Scholars speculate that they may hibernate in caves, or, like birds, fly south to avoid the colder weather. A researcher once tried to attach a GPS tracking device to a golden bat, but its body was too small to bear the weight of the battery—so researchers are still none the wiser.
Lin Liang-kong says that golden bat numbers reached nearly 1000 during the 1970s, but because of the impacts of land development and pesticide pollution, many habitats were destroyed. The number of golden bats sits currently at a depressing 50–60, so saving the golden bats is an urgent task.
In order to overturn people’s generally sinister impressions about bats, Zhang Hengjia, director of the Formosan Golden Bat’s Home, has held around 100 camps since 2006 to encourage the community to work together for their conservation.