Veronika Gerhard says: according to the Getty, "All species of animals are portrayed, from large lumbering elephants to tiny turtles and hamsters in the foreground."
The hamsters are GUINEA PIGS.
For details s. Faber Kolb "The Entry...", p.10
There are many many copies and variants of this composition. Some are listed by Ertz as being by Jan the Younger.
The back display the unidentified Antwerp panel maker's stamped mark 'RB'.