Is Cincinnati Zoo's Cheetah the Fastest Mammal
Cheetah's Animal 100 Meter Running Speed Record is Not Highest Speed
Sep 12, 2009
On Wednesday September 9, 2009 an 8-year-old female cheetah named Sarah set a running record at the Cincinnati Zoo. Sarah ran a certified 100-meter course in 6.16 seconds then soon broke her own record by running the course in 6.13 seconds. News reports claimed that Sarah was both the fastest cheetah and the fastest running land mammal.
Just how fast was this cheetah's run? Is this cheetah really the fastest land mammal?
How to Calculate Average Speed
To calculate the average speed of anything physicists divide the total distance by the time it takes to travel that distance. The formula is:
average speed = distance/time.
People often use the words speed and velocity interchangeably, but in physics they have different meanings. Velocity includes direction; speed does not.
To find the average speed a person or animal runs in a race, divide the length of the race by the time required to complete the race. The appropriate speed unit will be the distance unit per the time unit. If the distance is in meters and the time is in second, the speed is in meters per second, which can be converted to miles per hour.
Speed of Cheetah at Cincinnati Zoo
Dividing the 100 meter distance that the cheetah ran by her 6.13 second time gives an average speed of 16.2 meters per second. Multiplying this speed by 3,600 seconds in an hour and dividing by 1,609 meters in a mile gives the cheetah's average speed as 36.3 miles per hour.
Speeds of Other Cheetahs
This speed is impressive, but does not sound fast for a cheetah. Popular sources of information often cite a cheetah's top speed as about 65 to 70 miles per hour.
The most scientifically reliable estimate of these claims for a cheetah's speed seems to be the measurements reported by N.C.C. Sharp in volume 241 page 493 of the Journal of Zoology in 1997. Sharp made three trials timing a cheetah on a 201 meter (220 yard) course. Sharp's reported times were 7.0, 6.9, and 7.2 seconds. Taking the fastest trial gives an average speed for Sharp's cheetah of 29 meters per second or 65 miles per hour.
Sharp's cheetah did not start from rest, but was allowed an acceleration distance of about 20 yards to reach top speed. Sarah, the Cincinnati running cheetah's average speed of about 36 miles per hour is much slower. However Sarah started from rest and needed time to accelerate to top speed. Hence her top speed was faster than her average speed. It would be interesting to know Sarah's top speed during her run.
This comparison is therefore unfair to Sarah, however it does seem that Sharp's cheetah was faster.
Speeds of Other Mammals
Usain Bolt's human world record for 100 meters is at an average speed of 23.4 miles per hour. Humans are not close to outsprinting cheetahs.
On June 9, 1973 the famous race horse, Secretariat, ran the 1.5 mile Belmont stakes in 2 minutes 24 seconds. This time translates to an average speed of 37.5 miles per hour.
The Cincinnati cheetah, Sarah, may have run a world record 100-meter dash starting from rest, but claims that Sarah is the fastest land mammal seem exaggerated. Cheetahs and other mammals have been clocked at faster speeds under different conditions.
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