How Cheetah Really Hunt

Researchers at the Royal Veterinary College have captured the first detailed information on the hunting dynamics of the wild cheetah (Acinonyx jubatus) in its natural habitat. Using an innovative GPS and motion sensing collar they designed, Professor Alan Wilson and his team were able to record remarkable speeds of up to 58mph.

To date, 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.

Wilson’s team developed a tracking collar
equipped with a GPS module and accelerometers, magnetometers, gyroscopes. These sensors recorded precise position and velocity data of the animal’s movements.

Collar software monitored the accelerometers creating activity summaries for each brief hunting event. Overall, researchers recorded data from 367 runs by three female and two male adult cheetahs over 17 months (Figure 1).

cheetah

Figure 1. A cheetah wearing a GPS collar makes a sharp turn (From Wilson et al, 2013)

Data revealed that wild cheetah runs started with a period of acceleration, either from stationary or slow movement (presumably stalking) 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 acceleration after the speed returned to zero, indicating that the cheetah was subduing the prey – in this case mainly Impala, which made up 75% of their diet.

The average run distance was 173m. The longest runs recorded by each cheetah ranged from 407 to 559 m and the mean run frequency was 1.3 times per day, so, 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 (Figure 2).

cheetah1

Figure 2. Some of the hunt statistics from the study. a, Top speed, averaged over a stride, reached in each run color-coded for outcome. b, Distance covered in each run. c, Top speed in each run coded for terrain type. d, Peak acceleration and deceleration recorded in each run. (From
Wilson et al. 2013)

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 travelled, number of turns, or total turn angle. Rather, 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 likely reflect prey captures.

The acceleration power for the cheetahs was double that for racing greyhounds and more than three times higher than polo horses in competition. Interestingly, grip and maneuverability, rather than top speed, were shown to be key to hunting success. Hunts involved considerable maneuvering, with maximum lateral (centripetal) accelerations often exceeding 13ms
-2 at speeds less than 17ms-1 (polo horses achieve 6ms-2).

According to Professor Alan Wilson, “Although the cheetah is recognized 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.

Source: Modified from materials provided by the Royal Veterinary College, London.


Reference
Wilson, A. M., J. C. Lowe, K. Roskilly, P. E. Hudson, K. A. Golabek & J. W. McNutt (2013). Locomotion dynamics of hunting in wild cheetahs Nature DOI: 10.1038/nature12295


African Wild Dogs Fear Lions

There is no love lost between lions (Panthera leo)and African wild dogs (Lycaon pictus, Figure 1) on the plains or Africa. Lions often steal kills made by wild dogs and have been known to kill pups and occasionally adults. In fact, in the Moremi Game Reserve lions cause 47% of wild dog deaths according to Botswana researcher John McNutt. The need to avoid lion prides may be one of the reasons that wild dogs require such large home ranges.

    Steve Jurvetson
Figure 1. An African wild dog (Lycaon pictus). (From Steve Jurvetson/Flickr)

The hypothesis that threats from larger competitors like lions and hyenas limit wild dog population density and distribution has only recently been tested in the field. Hugh Webster, John McNutt, and Karen McComb played lion roars and hyena whoops to 8 packs of African wild dogs and observed their responses. The lion roars were from both male and female lions recorded in other African parks. These roars were presented as single lions roaring or as choruses of 3 lions roaring together. The hyena whoop calls were similarly recorded and presented to the wild dog packs.

Wild dog packs responded to lion roars by standing, facing the direction of the hidden speakers, rearing up on their hind legs to get a better view, and cautiously approaching the source of the roar. In dense habitats, however, the wild dogs quickly retreated (Figure 2).

wild_dogs1
Figure 2. A bar chart showing the mean time to retreat by wild dog packs’ in response to lion roars in habitats of differing density. (Webster et al., 2012)

Wild dogs responded very differently to hyena whoops (Figure 3). Instead of retreating, wild dog packs generally remained in the same area and eventually dozed off, suggesting that hyenas in the area do not pose a significant threat to the pack.

wild_dogs2
Figure 3. Wheel diagrams showing the direction and distance travelled by wild dog packs in the hour following playbacks of lion roars or hyena whoops. The playback loudspeaker is located 100 m north of this center point. (From Webster et al., 2012)

Interestingly, wild dog packs did not differ in their response when choruses of 3 lions were presented versus only a single lion roar. In fact, the only variable that explained wild dog behavior was the density of the surrounding habitat. Presumably, wild dogs are at greater risk of ambush by lions in dense vegetation where sight is limited.

These results indicate that lions may limit wild dog packs to areas on the periphery of lion ranges or to areas with less prey where the packs are less likely to encounter lions. As the authors point out, this has important implications for wild dog reintroduction programs. It may be best to avoid reintroductions in areas were lions are abundant.

References

Webster, H., McNutt, J., & McComb, K. (2012). African Wild Dogs as a Fugitive Species: Playback Experiments Investigate How Wild Dogs Respond to their Major Competitors Ethology, 118 (2), 147-156 DOI: 10.1111/j.1439-0310.2011.01992.x
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