Fruit bats in a Hong Kong garden—but what are they?

Last week AJP noticed a fruit bat roost in the garden of his flat in Kowloon Tong. The short-nosed fruit bats nibble the stems of palm fronds such that they partially collapse and form a sheltering umbrella under which the bats roost. We read that it is the males who set up such day roosts where they are joined by a harem of usually 1-6 females. So this bat has only been seen with one female—and she is sometimes absent for the day. Reports on bat numbers in the roost are eagerly awaited each day. Will he increase the size of his harem? Is it the same female with him? Who is she with when not in the roost? No soap opera can compete with a roost of fruit bats.

  

All the Hong Kong publications refer to this bat as Cynopterus sphinx, the Greater Short-nosed Fruit Bat. However, when I looked up this species in the final volume of that amazing series Handbook of the Mammals of the World, published at the end of 2019, I found that this species is not shown as occurring in Hong Kong. By contrast, the Lesser Short-nosed Fruit Bat, C. brachyotis, is shown occurring in an isolated patch of Guangdong Province. However, looking at the same distribution map on the IUCN Red List website, that distribution does not extend to Hong Kong. In fact neither species is shown as occurring in Hong Kong!

Partial distribution maps from the IUCN Red List website. Hong Kong is circled in RED

   

So what are the Hong Kong short-nosed fruit bats? Since there is an isolated patch of C. sphinx recorded for the Chinese mainland opposite Taiwan, could there be another patch in Hong Kong, or should the distribution of C. brachyotis be extended a little to the south-east? Given the quantity of literature on the fruit bat of Hong Kong it does seem surprising that little note of them seems to have been taken by those taking an encyclopaedic approach.

The entry for the Lesser in the Handbook does note: ‘Cynopterus brachyotis is often confused with C. sphinx and other species with which it overlaps in many physical dimensions’.

Clearly, more work is needed to put Hong Kong’s fruit bat—a protected species—to be put on the map, literally.

A very short video - look for the white-rimmed ears: