One difficulty faced by conservationists is getting hold of reliable statistics on the animals they are looking after.  For good reasion, many species of predators are rather shy.

In a paper just published in Current Biology a small group of researchers describe a clever low-cost solution.

Their idea is to take another well-known difficulty of doing field work in tropical forests – the endless swarm of bloodsucking leeches – and turn it into a scientific tool.

Realising that leeches can go for months without food, they have taken to capturing leeches and examining the stomachs for DNA, and in the process identified a number of previously believed to be extinct species.

More about this work can be found in the current edition of the Economist: