Zookeeper Vicky Fyson, at ZSL London Zoo, weighs and measures penguins during the zoo's annual weigh-in on Aug. 22, 2012, in London, England. The height and mass of every animal in the zoo, of which there are over 16,000, needs to be recorded. The measurements are collated in the Zoological Information Management System, from which zoologists can use the data to compare information on thousands of endangered species.
Meerkats are weighed and measured during the ZSL London Zoo 's annual weigh-in on Aug. 22, 2012, in London, England.
'Elton' the spectacled owl is weighed and measured during ZSL London Zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Grant Kother, at ZSL London Zoo, weighs and measures a giant tortoise during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Giraffes are weighed and measured during the ZSL London Zoo 's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Don McFarlane, at ZSL London Zoo, weighs and measures an African Millipede during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
A zookeeper at ZSL London Zoo prepares to weigh and measure the giraffes during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Meerkats are weighed and measured during the ZSL London Zoo 's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Don McFarlane, at ZSL London Zoo, weighs and measures an African Millipede during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
A zookeeper at ZSL London Zoo prepares to weigh and measure the giraffes during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Vicky Fyson, at ZSL London Zoo, weighs and measures penguins during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Vicky Fyson, at ZSL London Zoo, weighs and measures penguins during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Meerkats are weighed and measured during the ZSL London Zoo's annual weigh-in on Aug. 22, 2012, in London, England.
A zookeeper at ZSL London Zoo prepares to weigh and measure the giraffes during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Meerkats are weighed and measured during the ZSL London Zoo 's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Vicky Fyson, at ZSL London Zoo, weighs and measures penguins during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Vicky Fyson, at ZSL London Zoo, weighs and measures penguins during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Vicky Fyson, at ZSL London Zoo, weighs and measures penguins during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
A zookeeper at ZSL London Zoo prepares to weigh and measure the giraffes during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Don McFarlane, at ZSL London Zoo, weighs and measures an African Millipede during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
A zookeeper at prepares to weigh and measure 'Elton' the spectacled owl during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
A zookeeper at ZSL London Zoo prepares to weigh and measure 'Elton' the spectacled owl during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
'Elton' the spectacled owl is weighed and measured during ZSL London Zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Grant Kother, at ZSL London Zoo, weighs and measures a giant tortoise during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Grant Kother, at ZSL London Zoo, weighs and measures a giant tortoise during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Zookeeper Grant Kother, at ZSL London Zoo, weighs and measures a giant tortoise during the zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Giraffes prepare to be weighed and measured during the ZSL London Zoo's annual weigh-in on Aug. 22, 2012, in London, England.
A giraffe prepares to be weighed and measured during the ZSL London Zoo's annual weigh-in on Aug. 22, 2012, in London, England.
Giraffes prepare to be weighed and measured during the ZSL London Zoo's annual weigh-in on Aug. 22, 2012, in London, England.