Black gold from Cambodian bats

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Cambodian farmers in the Mekong River Delta have a long history of attracting bats to their farms. Merlin has documented with photographs the step-by-step process of this win/win situation for the farmers and the bats. (Be sure to watch the video below!) 

In Cambodia farmers attract bats to artificial roosts, collect their droppings, and sell the guano for fertilizer. Each roost consists of 10 bundles of dried palm fronds, each consisting of five fronds wired together and hoisted, one bundle at a time, to the top of a palm tree. One farmer reported earning nearly $900 US per year per roost, that farmer relying on 10 roosts for extra income. Climbing palm to install a new bat roost.

Cambodian farmers cut and dry the fronds of sugar palms and wire them together in bundles of 4-5 fronds each, 10 bundles per tree. Although these palms are common, most do not have enough dead fronds hanging close enough together to provide good bat roosts. Observant people apparently noticed that bats came only when several fronds hung close together and figured out that if they cut fronds and bundled them, they could attract more bats.

A man climbs the palm on a bamboo ladder and hoists a roost in place.

bats in cambodia

Long bamboo poles, securely strapped to palm trunks (with short side branches are used as ladders, enabling farmers to climb 50 feet or more. They hoist the bundles, one at a time, tying them to form a dense skirt beneath the crown of the tree. Once they’re wired firmly in place, they form secure shelter for the Lesser Asiatic house bat (Scotophilus kuhli).

The primary goal is collection of guano for crop fertilizer. To do this, some farmers spread mosquito netting to catch the droppings, while others simply sweep the droppings from hard earth beneath the tree. 

These wired-together bundles have been dropped to the ground and now will be replaced. Once or twice annually the bats abandon their roost, apparently to escape from parasites and will be replaced with a new one, raised and secured one bundle at a time. Farmers always have new roosts ready nearby so the bats don’t leave the area.

On average, Heurm Oaurn collects 10 buckets of guano every three days. Each bucket holds approximately 3 ½ kilos and sells for about $1.50 US, which means she’s making approximately $120 US per month. This provides an excellent supplement to her family income while also helping the bats.

Lesser Asiatic yellow house bat (Scotophilus kuhlii), Vespertilionidae