Use your pooper-scooper with pride
SARA ABDULLA
Michael Kohn of the University of California, Los Angeles, California and colleagues, have been collecting coyote droppings in the Santa Monica Mountains near Los Angeles-- not out of civic pride or childish perversity, but in order to estimate just how many of these wild, dog-like carnivores live in the area.
Analysis of the genetic material contained within animal feces is a quick and powerful new way of assessing the population size, sex ratios, and familial relationships of rare and endangered large mammals, as the researchers explain in Proceedings of the Royal Society of London.
Data on population dynamics are essential for conservation management and ecological research. But existing methods of collecting such information are fraught with problems. Direct counts can be inaccurate because individuals are hard to detect, and trapping can be difficult and injurious to the animals concerned.
This is why Kohn and colleagues extracted DNA from hundreds of droppings that they collected from paths and roadways where coyotes, like most carnivores, defecate to mark their territorial boundaries. The team then screened these genetic blueprints for species-, sex- and individual-specific markers.
Their survey turned up approximately equal numbers of males and females and about the same amount of multiple samples from each individual. So whereas male coyotes, just like domesticated dogs, urinate far more than females, both sexes defecate equally frequently. The researchers were able to work out the probable size of the coyote population from the number of genetically unique individuals they had detected.
To compare the feces-genotyping method of population analysis with more conventional population analysis methods, Kohn’s group also surveyed the same area using trapping, tracking and photography. The results showed that studying feces provides a reliable, non-invasive way of taking a social snapshot of mammals such as coyotes, where all the individuals defecate at the same rate, regardless of sex, age or social status. "The systematic collection of faeces followed by molecular typing," the group conclude, "provides a near instantaneous estimate of population size, sex ratio, relatedness and [geographical] range that avoids the problems of capture and handling." Never has the pooper scooper had such power!
© Macmillan Magazines Ltd 1999 - NATURE NEWS SERVICE
SARA ABDULLA
Michael Kohn of the University of California, Los Angeles, California and colleagues, have been collecting coyote droppings in the Santa Monica Mountains near Los Angeles-- not out of civic pride or childish perversity, but in order to estimate just how many of these wild, dog-like carnivores live in the area.
Analysis of the genetic material contained within animal feces is a quick and powerful new way of assessing the population size, sex ratios, and familial relationships of rare and endangered large mammals, as the researchers explain in Proceedings of the Royal Society of London.
Data on population dynamics are essential for conservation management and ecological research. But existing methods of collecting such information are fraught with problems. Direct counts can be inaccurate because individuals are hard to detect, and trapping can be difficult and injurious to the animals concerned.
This is why Kohn and colleagues extracted DNA from hundreds of droppings that they collected from paths and roadways where coyotes, like most carnivores, defecate to mark their territorial boundaries. The team then screened these genetic blueprints for species-, sex- and individual-specific markers.
Their survey turned up approximately equal numbers of males and females and about the same amount of multiple samples from each individual. So whereas male coyotes, just like domesticated dogs, urinate far more than females, both sexes defecate equally frequently. The researchers were able to work out the probable size of the coyote population from the number of genetically unique individuals they had detected.
To compare the feces-genotyping method of population analysis with more conventional population analysis methods, Kohn’s group also surveyed the same area using trapping, tracking and photography. The results showed that studying feces provides a reliable, non-invasive way of taking a social snapshot of mammals such as coyotes, where all the individuals defecate at the same rate, regardless of sex, age or social status. "The systematic collection of faeces followed by molecular typing," the group conclude, "provides a near instantaneous estimate of population size, sex ratio, relatedness and [geographical] range that avoids the problems of capture and handling." Never has the pooper scooper had such power!
© Macmillan Magazines Ltd 1999 - NATURE NEWS SERVICE