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Solar-Powered Collar Tracks Hunting Cheetahs' Methods

posted 12 Jun 2013, 11:30 by Mpelembe   [ updated 12 Jun 2013, 11:31 ]

Solar-and-battery powered tracking collars have given British researchers new insight into the hunting habits of the cheetah, one of the world's swiftest predators

DE WILDT, SOUTH AFRICA (RVC) - Researchers have captured what they say are the first dynamics of the wild cheetah hunting in its natural habitat, using a GPS and motion sensing collar. The team from Britain's Royal Veterinary College showed the wild cat reaching speeds of up to 58 mph (93 kph) during hunts at the Ann van Dyke Cheetah Centre in De Wildt, South Africa. Captive cheetahs have been recorded at speeds of up to 65 mph (105 kph).

The team, led by Professor Alan Wilson, developed the solar-and-battery powered tracking collar, which was equipped with a GPS module, accelerometers, magnetometers, and gyroscopes. Sensitive to the animal's movements, they say it succeeded in delivering more accurate measurements than previous speed tracking efforts. These usually involve testing captive animals, rather than wild varieties, chasing a lure in a straight line as illustrated in video released by the team. But, prior to these experiments, nobody had been able to gauge the animals' speed in the wild.

For wild cheetahs, estimates of speed have only ever been made from direct observation or film, in open habitat and during daylight hours.

Overall, researchers recorded data from 367 runs by three female and two male adult cheetahs over 17 months. An episode of feeding after a run indicated hunting success, and was identified in the activity data by consistent, low-magnitude acceleration.

Data revealed that wild cheetah runs started with a period of acceleration, either from stationary or slow movement up to high speed. The cheetahs then decelerated and manoeuvred before prey capture. About one-third of runs involved more than one period of sustained acceleration. In successful hunts there was often a burst of accelerometer data after the speed returned to zero, interpreted as the cheetah subduing the prey - in this case mainly Impala, which made up 75 percent of their diet. The team was also able to identify various factors that make up a successful hunt.

"Although the cheetah is recognised as the fastest land animal, very little is known about other aspects of its notable athleticism, particularly when hunting in the wild. Our technology allowed us to capture what to our knowledge is the first detailed locomotor information on the hunting dynamics of a large cursorial predator in its natural habitat and as a result we were able to record some of the highest measured values for lateral and forward acceleration, deceleration and body mass," said Wilson.

The collar was powered by a combination of solar cells, rechargeable and non-rechargeable batteries. Collar software monitored the accelerometers to create activity summaries and detect the brief hunting events and adapted collar operation to battery voltages and time of day, meaning that researchers only captured data during a hunt.

The cheetahs used were part of a continuing study by the Botswana Predator Conservation Trust in the Okavango Delta region of Northern Botswana. The results, from the team at the Royal Veterinary College's Structure & Motion Laboratory, are published on Wednesday (June 13) in the journal Nature.