The World’s Fastest Runner – Greg Wilson – National Geographic (2012)

A well-designed filming set up to capture the motions of running Cheetahs.

Since late MIT professor Doc Edgarton’s time highspeed cameras have evolved wonderfully enabling technical capabilities for producing great slow motion films. In this production the filming crew used a Phantom Flex highspeed recording camera. The following talk by the director Greg Wilson gives us the behind-the-scenes view of the project. The entire set up was constructed on the running alley specially designed for exercising the Cheetahs of Cincinnati Zoo:

The speed of recording at 1200 frames per second enables extremely smooth capture. At that rate, a four second footage can be smoothly expanded into more than three minutes. Here in this project, the entire sequence is two seconds long in real time but the slow motion capability impressively stretches the footage into two minutes. Greg Wilson took the opportunity and collaborated with the Cincinati Zoo where the caretakers have developed a great expertise in these regular exercise runs. Caretakers use a manually controlled spongy lure dragged at high speeds. The familiar cat behavior manifests itself in chasing the spongy object. Caretakers’ dexterity help keeping the animal engaged in the fast moving lure.

The footage provides a great visual template on which science of movement based on skeletal and muscular anatomy is shown. During a typical run, a Cheetah can leap 25 feet on a single stride and can reach speed of 70 – 75 miles per hour. However research shows that the fastest animal on land rarely uses its top speed to capture prey. Instead, these animals use their ability to accelerate and rapid changes in direction when hunting.

This is an ultra-fast predator co-evolved to catch a fast prey. The long spine and the small skull anatomy reflects a super-tuned evolutionary adaptation for speed. The Cheetah has non-retractable claws and the ratio of fast twitch muscle fibers to that of slow twitch in its hind legs are more than any other cat species.

Cheetahs are hallmark example of reduced genetic diversity in large carnivores. When compared with other wild cat speces it has less than 5 percent of the genomic diversity of other wild cats. This diversity erosion is due to a series of genetic botleneck in its three-million-year-old history as a species.

Did you know that cheetahs used to live in North America until about 100,000 years ago? In Human terms this corresponds to the middle paleolithic. Fossil record indicates that they moved across the Bering Strait into Asia, and Africa. By the time they reached Africa their numbers became drastically low which forced them to inbreed. Their populations got hammered again during the Pleistocene epoch.

Many institutions including the Cincinati Zoo are collaborating to establish a breeding program to enrich and recover the lost genetic diversity in the entire African Cheetah population. Cheetah populations continue to decline fast. In the last 100 years 90 % of Cheetah have been lost.

Predators exert a great deal of pressure on plant eaters and reduce plant consumption. Ecologists call this phenomenon top-down trophic cascade. Three ecologists Nelson Hairston, Frederick E. Smith and Lawrence B. Slobodkin introduced the concept what is now generally known as The Green World Hypothesis. According tho the hypothesis predators keep the plant eater populations in check. Even the presence of predators induce a big change in herbivore behavior.
Thus, when predator numbers decrease plants face increasing herbivore pressure. Ecologists have documented this in many terrestrial and aquatic ecosystems. In California sea urchins over graze kelps in the absence of sea otters. Wolves restored the vegetation around rivers in Yellowstone by keeping deer and elk numbers in check. In Africa when leopards decline baboon populations grow and start attacking farm plantations. Similarly when predators disappear as a survival response plants are forced to evolve defensive thorns and bitter chemicals known as secondary compounds. Thorny Acacia trees are more common in areas where impala experience a low risk of predation by wild dogs. A related Acacia, without thorns, is most abundant in areas where risk of predation is high, and so the number of hungry impala is low.

 

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