Current Events in Context: When agility trumps speed

Image of a cheetah. (Photo: Mara 1)

The cheetah is the fastest mammal on earth, clocked at speeds exceeding 60 miles per hour while in captivity. Although it’s much harder to measure their speed in the wild, experts have long assumed that swiftness is what makes them such formidable hunters. But scientists from London’s Royal Veterinary College have recently discovered that a cheetah’s true talent lies more in its agility and maneuverability.

They actually hunt their prey at somewhere much closer to 30 miles per hour, only slightly faster than a human at top speed. Yet in stark contrast with human biomechanics, cheetahs can quickly stop, change directions, and accelerate with startling effectiveness.

The key to the discovery was the perfection of a lightweight, solar-powered collar—a tracking device ten years in the making—that contained a GPS module, accelerometer, magnetometer and gyroscope to precisely track the movement of these animals in three-dimensional space.

Five cheetahs in Botswana were outfitted with the collars and tracked for 18 months in the wild. Data from a total of 367 runs were recorded with remarkable precision, allowing a rich portrait of these animals to emerge.

We learned, for example, that cheetahs hunt as much in dense shrub as open fields, and they will hunt throughout the day, rather than just in the morning, as was commonly believed.

What the data revealed about the cheetah’s locomotor skills was most impressive: They can accelerate by 7 miles per hour in a single stride—four times quicker than the fastest human, Usain Bolt. They can also reduce their speed by almost 9 miles per hour in a single stride, which greatly increases their ability to sharply change direction.

The experiment opens up new possibilities in several disciplines, from biomechanics to ecology, and OpenCourseWare offers a broad spectrum of courses to learn more about them. Here’s a small sample:

  • 9.20 Animal Behavior covers various approaches to the study of animals and their adaptive behavior, including habitat selection, feeding, learning and reproduction.
  • 6.832 Underactuated Robotics applies biomechanical principles to the design of autonomous, moving robots.
  • 2.003J Dynamics and Control I covers the science of kinematics, a branch of classical mechanics that describes the motion of points, bodies and systems of bodies—the geometry of motion.

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