Last seen in 1936, the mysterious Pouch Bearing Sheathed Tailed Bat has made a comeback – after 75 years. Recently sighted by researchers Ranil Nanayakkara and Nilantha Vishvanath, the discovery of the bat that was ‘missing’ has excited wildlife enthusiasts.
The Pouch Bearing Sheathed Tailed bat, bearing the scientific name Saccolaimus Saccolaimus, was listed as globally threatened by the IUCN Redlist, and the Biodiversity Secretariat. Globally, efforts have been put in place to bolster populations of these species but the difficulties in spotting and carrying out research have hindered conservation efforts. Being an insectivorous species, these bat populations have been threatened by the use of pesticides.
Ranil and Vishvanath discovered the species roosting in the hollow of a coconut tree, at Yatawehera estate, Kurunegala. The roosting site was about 8-10 feet from the ground and there were four male bats occupying the hollow. The specimens were captured to get the necessary measurements essential for identification, before they were released back to the roosting site.
“It was quite a thrill to see this species,” says Ranil. “The Pouched Sheathed Tailed Bat is extremely rare, as the deficit of information for 75 years suggests, but it is also one of the most unique, having features that sets it apart. They are highly intelligent and have complex social structures. You have to be out in the field to know this.”
Major. W.W.A. Phillips – the pioneer of small mammal research in Sri Lanka had mentioned this particular species, but a clear detail was not possible due to lack of sightings. The species was last recorded in 1936 in Cheddikulam, by E.C. Fernando of the National Museum of Sri Lanka.
Saccolaimus saccolaimus is one of the three species of sheathed tailed bats found in Sri Lanka which belongs to a family with the unique feature of tails protruding from the interfemoral membrane (the membrane that extends between the inner margins of the legs of bats).
This is a medium-sized insectivorous bat that uses echolocation to find its way in the darkness and capture its prey. Its coat is generally dark brown to almost black mixed with whitish hairs giving a mottled appearance with the face and wings being almost black.
It can be distinguished from others of its genus having long wings, and the presence of a gular sac beneath the chin along with the very dark colouring. The other distinguishing feature of this bat is the lack of a radio metacarpal pouch (a pocket on the ventral side of the wing found in some bats) on the wing, whereas it is prominent in the other two species found on the island
Their echo-location capabilities are unparalleled, states Ranil. “They could detect an object as thin as a strand of hair from several hundred metres away, a feat that cannot even be matched by the latest radar technologies.” The saccolaimus saccolaimus is roughly about 12 cm in length. Apparently their miniature size has also been a barrier for sighting.
They fly at great speed outstripping all other bats in Sri Lanka and with their long narrow, pointed wings they might be almost mistaken for some kind of swift. As they fly they generally herald their approach by loud high pitched squeaking cries.
Driven purely by their passion for wildlife and the thirst for knowledge, Ranil who is currently doing his thesis carries out extensive research along with Nilantha
This rediscovery has resulted from an island-wide survey currently being conducted by Biodiversity Education and Research (BEAR) on lesser known mammals.