A picture of a tiny tiger meeting a bear cub is just one image of London Zoo in a photograph archive which can now be seen online.
Other highlights of the Zoological Society of London's (ZSL) album, which dates back to the 19th Century, include a keeper with a snake from 1870.
The archive also includes present-day pictures of some of the more exotic creatures at London Zoo
Copies will be sold to raise money for the ZSL's global conservation work.
The ZSL's Caroline George said: "Going through the photos and slides in the library has been a reminder of ZSL London Zoo's astonishing history, and the changes it has undergone in the last century.
"They are particularly fascinating because the gradual transformation of ZSL London Zoo really mirrors the broader changes in our understanding of the environment and animal husbandry too."
The ZSL photo archive can be seen by clicking