Wednesday, January 25, 2012

One Per Cent - Vultures skeletonise corpse for the sake of forensics

Paul Marks, senior technology correspondent
A wake of vultures scavenge an animal carcass: what do they do to people?

Ever entertained the idea of leaving your body to science? Even if you have, you can scarcely have considered the strange fate of one donated corpse that has just been revealed in the journal Forensic Science International: a donor's body was left in a Texan wilderness so that vultures could scavenge and "skeletonise" it - and distribute the remains far and wide.
This wasn't for some horror movie - even though the process was captured on video. The aim was to discover how long it takes vultures to discover a body, how long it takes to reduce a body to bones - and how far the creatures are likely to distribute the parts they don't eat.
There's good reason for this grisly work. Researcher Katherine Spradley of Texas State University in San Marcos say that when human body parts are found in wilderness areas in the US, detectives can be at a loss as to the time of death. Has the body been attacked locally by animals? Or perhaps torn apart by a vultures?
"Vultures throw off the time-since-death estimation significantly. Prior to our study, if you came across disarticulated remains you would assume that they were dismembered by a carnivore - and then remain puzzled when there are no gnaw marks typical of carnivores," Spradley told New Scientist.
With colleagues Alberto Giordano and Michelle Hamilton they placed a body from the Willed Body Donation Program in the grounds of the Texas State University's Forensic Anthropology Research Facility - "an outdoor human decomposition laboratory" similar to the storied 'body farm' in Tennessee - and left it monitored by a motion-sensing video camera.
The video camera was triggered after 37 days when a 30-strong wake of American black vultures - Coragyps atratus - discovered the body and set to work consuming it. They reduced it to bones in just five hours. Both results surprised the researchers: pigs have been found and consumed by vultures within 24 hours of being left in the facility. And the skeletonisation was much quicker than the day they had expected it to take. This will feed into future time-of-death calculations.
The spatial pattern of discarded body parts was mapped by the team using GPS over the next 15 weeks - as vultures came back and distributed the remains still further - and the researchers hope this dispersal pattern will aid future forensics work, too.
"We now need more studies replicating this pilot study," says Spradley."There could be differences in the time of year and temperature that affects how active the vultures are."

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