Sarah, a cheetah who was considered the world’s fastest land mammal, died at the Cincinnati Zoo & Botanical Garden in the US last week. She was 15 years old and was euthanized due to her “diminishing quality of life”, said the zoo in a statement. The average life span of a cheetah is 8-12 years. Sarah was designated as the fastest by National Geographic magazine in 2012, when she ran 100 metres in a record time of 5.95 seconds. She beat her own previous world record of 6.13 seconds in 2009. To put Sarah's record in perspective, the world record for 100 metres is 9.58 seconds, set by Usain Bolt in Berlin on August 16, 2009.