Poached skins matched to tigers
BBC NEWS, 11 March 2009 Victoria Gill, Science reporter
A new piece of software is able to identify individual tigers by the unique stripe patterns on their coats.
This tool, the developers say, will make it easier to estimate tiger populations and aid conservation efforts.
It is also able to match skins sold on the black market to photographs of the animals taken using camera traps.
The team of scientists based in the UK and India report its invention in the journal Biology Letters.
The program was based on software originally designed to scan the markings of grey seals and identify them from photographs.
The researchers adapted this for tiger stripes, and combined it with a 3D map of the surface of a tiger's body.
This
enabled them effectively to unwrap the pattern of stripes from an image
of a live animal and match it to picture of the flat skin.
Dr
Ullas Karanth, a researcher from the Wildlife Conservation Society
India Program, worked on the project with the UK-based company
Conservation Research.
Shooting Tigers
"Tigers are very secretive animals and it is a major challenge to estimate their numbers," Dr Karanth explained.
Over
a decade ago, he came up with the idea of using camera traps - hidden
cameras operated by trip wires - to monitor tiger populations.
“Until camera trapping is an ongoing process, the usefulness of this amazing software will be limited ” Belinda Wright, Wildlife Protection Society of India
Since
then researchers have used a combination of this automated photography
- and tagging and tracking the animals - to monitor their numbers.
But
each new photograph of a tiger had to be compared with every animal in
a database of images. It is a laborious process, Dr Karanth says.
"No
piece of software is as good at discerning shapes as the human brain,
but we can use this to shortlist the most likely matches, and then
eyeball the photos in that shortlist," Dr Karanth told BBC News. "It's
a very powerful tool."
While they were testing the software, Dr
Karanth and his colleagues found images of three tigers that, it turned
out, had later been killed by poachers. This inspired the designers
to build in a forensic tool that could be used to trace the origin of
any skin to a photograph of the tiger.
They also adapted it for other species with unique markings, including leopards, zebras and salamanders.
More needed
Belinda
Wright is executive director of the Wildlife Protection Society of
India, an organisation that investigates every tiger death in the
country.
She says simplifying the process of identifying tigers
from camera trap images would be "very beneficial" to conservation
research.
But, she warned, opportunities to find the origin of a confiscated tiger skin are rare.
"Skins are often seized in very remote locations, and we often don't get decent photographs of them," Ms Wright explained.
Further, camera trapping is not yet carried out continuously in all of the areas throughout India where tigers live.
This
will be necessary, she says, to maintain a census of the tiger
population. "Until camera trapping is a regular and ongoing process,"
said Ms Wright, "the usefulness of this amazing software will be
limited."
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