Rhinolophus trifoliatus
Common name: The Trefoil Horseshoe Bat
Rhinolophus trifoliatus is a very distinctive bat with its yellow noseleaf and ears
Distribution of Rhinolophus trifoliatus
Physical Description
Nose: Like all horseshoe bats, Rhinolophus trifoliatus has a very distinctive noseleaf that extends to cover much of the face but only a few species have the two rounded bits, called lateral lappets that are either side of the sella, in the middle of the noseleaf just above the nostrils. The noseleaf is also a very distinctive yellow color and the connecting process is large and rounded.
In this photo we have circled the two lateral lappets of the noseleaf
Fur: The fur is long and fluffy and a pale buffy-gray to light brown.
Ears: The ears are large and yellowy, particularly at the base. Like all Rhinolophus there is no tragus, but there is a very pronounced antitragus.
Wings: The wing membrane is a tan-brown color, and the wings are broad and rounded, enabling Rhinolophus trifoliatus to maneuver through the forest with ease.
Tail: Like all Rhinolophus 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 millimeter 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. In older individuals of R. trifoliatus, the edge of the tail membrane tends to be yellowish.
In addition to the yellow noseleaf and ears, R. trifoliatus also has yellow elbows and yellow knees!
Size: Rhinolophus trifoliatus is one of our larger horseshoe bats, with an average forearm length of about 51 mm and average weight about 13.5 g.
Rhinolophus trifoliatus roosting under a palm leaf in the forest understorey. If you look closely you might just be able to see the aerial from the radio-transmitter sticking up from its back
Ecology
A common species that is found in primary and secondary forests at all elevations, and in mangrove forests. It is often found in the understorey of the forest. From our radio-tracking studies we know that it roosts singly under broad leaves and palms, where its pale gray-brown and yellow coloring may provide camouflage as it roosts in trees among dead leaves.
Rhinolophus trifoliatus is a “perch hunter”, meaning it perches from a branch in the forest understorey, twirling around as it scans the clear area below with echolocation for insects to fly by. The wing flutter of the insect prey creates a very distinctive echo, and once located, the bat swoops out to catch its prey and returns to the perch to eat it. Perch hunting is very energy efficient, and the bat can save up to seven times the energy needed by other bats which hunt and eat insects while flying.
Where they are found
Peninsular Malaysia, SW Thailand, Myanmar, NE India, Borneo, Sumatra, Java.
