Wednesday, 19 June 2013

During a Hunt, wild Cheetah accelerate fast and reach speeds of maximum 58 Miles/ Hour



Researchers at the Royal Veterinary College have captured the first detailed information on the hunting dynamics of the wild cheetah in its natural habitat. Using an innovative GPS and motion sensing collar, Professor Alan Wilson and his team were able to record remarkable speeds of up to 58 miles per hour (or 93 kilometers per hour). As of now, measurements of cheetah locomotion mechanics have only been made on captive animals chasing a lure in a straight line, with few studies eliciting speeds faster than racing greyhounds. For wild cheetahs, estimates of speed have only ever been made from direct observation or film, in open habitat and during daylight hours.


The team, led by Professor Wilson, developed a tracking collar equipped with a GPS module and electronic motion sensors (accelerometers, magnetometers, gyroscopes) capable of delivering processed position and velocity data and sensitive to the animal's movements. 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. 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 maneuvered 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% of their diet. The average run distance was 173 m. The longest runs recorded by each cheetah ranged from 407 to 559 m and the mean run frequency was 1.3 times per day. Even if some hunts were missed, high speed locomotion only accounted for a small fraction of the 6,040-m average daily total distance covered by the cheetahs.


The team was also able to identify factors that make up a successful hunt. Successful hunts involved greater deceleration on average, but there was no significant difference in peak acceleration, distance traveled,  number of turns or total turn angle. This indicates that outcome was determined in the final stages of a hunt rather than hunts being abandoned early to save energy or reduce risk of injury, and the higher deceleration values may reflect actual prey capture. The greatest acceleration and deceleration values were almost double values for polo horses and exceeded the accelerations reported for greyhounds at the start of a race. The acceleration power for the cheetahs was four times higher than that achieved by Usain Bolt during his world record 100 meters run, about double that for racing greyhounds and more than three times higher than polo horses in competition.


Grip and maneuverability rather than top speed, were shown to be key to hunting success. Hunts involved considerable maneuvering  with maximum lateral accelerations often exceeding 13ms-2 at speeds less than 17ms-1 (polo horses achieve 6ms-2). Professor Alan Wilson, said: "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 loco-motor 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. In the future, equivalent data for other wild cursorial species would enhance what we know about natural speed, agility and endurance, and provide detailed information on ranging behavior in the wild. For example, information on habitat selection by endangered species detailing where animals are commuting, hunting and resting would be informative when attempting to evaluate wildlife-protected areas." The cheetahs used in this study were part of a continuing study by Botswana Predator Conservation Trust in the Okavango Delta region of Northern Botswana.










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