ABOVE: This Colugo Galeopterus borneanus regularly visits the Meriuk Farm Stay orchards at Tutong in Brunei to lick the bark of the Binjai trees. The area circled in green on this tree trunk is a particularly favoured area. (The colugo moved sideways after a flashlight was shone on the bark.) The green arrow points at an area of leaking sap which dries black a characteristic of trees in the Anacardiaceae mango family
The colugo has been licking the area area to the left of her body and above her head which appear slightly damp. Areas of grey lichen appear to make no difference to the preferred areas and are licked indiscriminately along with the surface bark which is slightly worn away as if rubbed lightly with sandpaper.Areas of blackish bark where sap has leaked out and turned black in the past appear to be particularly preferred by the colugo. The sap of trees in the Anacardiaceae mango family are a known poison (Local name Rengas) which may cause a severe allergic reaction to humans on contact.
This article above on Rengas Poisoining or Anarcard Dermatitis is copied from James LaFrankie’s excellent book Trees of Tropical Asia. This book is an essential guide for anyone interested in the ecology of Borneo’s forests.
Jungle Dave the manager of Meriuk Farm Stay pointing to an area of bark preferred by the colugo. The colugo only visits at night and rests elsewhere during the day.Another Binjai tree in the Meriuk Farm Stay orchards. This tree is also visited by the colugo at night for the purpose of bark licking.Binjai also known as Beluno in Sabah is a wild mango Mangifera caesia which is often grown in home orchards in Borneo. There are two common varieties one which has a smooth green skin and another with a rough brown skin as shown above.