Zookeepers measure the length of a pueblan milk snake in the Reptile House of ZSL London Zoo as part of their annual weighing and measuring of their animals on August 25, 2011 in London, England. The heights and weights of over 750 different animal species at the zoo are recorded into the International Species Information System, to monitor their health and share the data with other zoos across the world. (Photo by Oli Scarff/Getty Images)

Lance Corpral Johnnie Miller of the Household Cavalry rehearses at Floors Castle in preparation for massed Pipe Band day on August 26, 2011 in Kelso, Scotland. The event, being held on August 28, will feature the first Scottish performance of the Household Cavalry's Musical ride in over 10 years. (Photo by Jeff J Mitchell/Getty Images)

A mahout removes the prosthetic from Motala, age 50, at the Friends of the Asian Elephant (FAE) elephant hospital in the Mae Yao National Reserve August 29, 2011 Lampang,Thailand. Motala lost a foot many years back after stepping on a land mine and now is on her third prosthetic, as they need to be changed according to the weight of the elephant. (Photo by Paula Bronstein/Getty Images)

An installation consisting of a series of bird boxes is displayed in a tree in Duncan Terrace Gardens in Islington on March 24, 2011 in London, England. The boxes by artists Bruce Gilchrist and Jo Joelson of “London Fieldworks”, were designed to reflect the architecture of the Georgian terraces and flats that surround the park in the community gardens. (Photo by Dan Kitwood/Getty Images)

Solana Plains (R) escorts a distraught Elijah West, cousin of Troy Davis, out of the Towaliga County Line Baptist Church that is across from the Jackson State Prison for the planned execution of inmate Troy Davis on September 21, 2011 in Jackson, Georgia. (Photo by Jessica McGowan/Getty Images)

A masked Palestinian uses a board to protect himself during clashes with Israeli forces which occurred shortly before Palestinian leader Mahmoud Abbas' speech to the the United Nations General Assembly, on September 23, 2011 in Qalandia, West Bank. (Photo by Ilia Yefimovich/Getty Images)

Singer Jason Derulo performs during his Flash Mob with Knicks City Dancers outside of Madison Square Garden on September 28, 2011 in New York City. (Photo by Mike Coppola/Getty Images)

Sheep are waiting in Via Manzoni before the final filming of the Last Shepherd on October 1, 2011 in Milan, Italy. Directed by Marco Bonfanti, L'Ultimo Pastore (The Last Shepherd) tells the story of the life of Renato Zucchelli, the last nomadic shepherd in Milan. (Photo by Pier Marco Tacca/Getty Images)