Charles Darwin loved to visit the London Zoo. He wrote to his sister Caroline in April 1831 that ‘what I liked most in all London is the Zoolog[ical] Gardens: on a hot day when the beasts look happy and the people gay it is most delightful’. In March 1838, after returning from his voyage on the Beagle, Darwin visited the zoo again. He was fortunate enough to see the rhinoceros emerging from her house and galloping in the enclosure ‘surprisingly quickly, like a huge cow’. The elephant in the next yard responded to his neighbour and began ‘trotting himself’ and ‘squealing & braying like a half dozen broken trumpets’. The most exciting attraction of the year was, however, Jenny, the first orangutan exhibited to the public at the London Zoo. Darwin observed her intelligence and emotional expression and compared her to a human child: