Hipposideros ridleyi
Common name: Ridley’s Roundleaf Bat
Hipposideros ridleyi has quite a limited distribution
Look at the characteristic disk between the nostrils in the anterior noseleaf.
Physical Description
Nose: Like all roundleaf bats Hipposideros ridleyi has a very distinctive noseleaf, but it is particularly large in this species and tends to cover much of the face. The noseleaf is a dark greyish-brown and it is unusual in that the skin between the nostrils is expanded to create a disk in the middle of the front part of the noseleaf.
Fur: The fur on the upperparts is a uniformly dark brown, with the fur on the underparts slightly paler.
A roost found by radio-tracking at Krau. The tree was at least 30 m tall before it fell, providing a long secure hollow for the bats.
Ears: The ears are very large – between 24 and 28 mm long and are a dark brown.
Wings: Like the ears and noseleaf, the wings are a dark brown, and very broad and rounded, so this species is very manoeuvrable in the forest.
Tail: Like all Hipposideros, a small tail membrane stretches between the legs, but doesn’t go much beyond the ankle. The tail itself is fully enclosed by the membrane, with maybe just a one or two millimeters of the tail poking out beyond the edge. At each ankle, there is a small rod of cartilage called a calcar, to which the tail membrane is attached, which helps the bat control the position of the membrane in flight.
Size: Because of the huge ears, Hipposideros ridleyi tends to look bigger than it actually is; the average forearm is about 49 mm, and average weight about 9 g.
Inside the tree hollow was a small colony of females with their juvenile young. See if you can spot the orange reflector on the radio-transmitter on one of the bats.
Ecology
One of the most threatened bats in Malaysia; it is only found in Peninsular Malaysia and Sabah, and there are few populations left. Found in primary lowland rainforests, very little is known about its ecology. It has been found roosting in small groups of up to 15 females in man-made structures like culverts and drainage pipes. Radiotracking studies in Krau Wildlife Reserve found them roosting in deep hollows of large fallen trees. These were mainly all-female/juvenile roosts of 4 to 11 individuals, and adult males were only occasionally present.
Where they can be found
Peninsular Malaysia and Borneo
