I like the basilisk in the top left of the sign! I thought maybe it was their logo but it isn't on the elephant sign, and their logo is a rhino in any case.
I believe the basilisk is there because at one point there were terrariums with reptiles in the building. Though maybe a Polish speaker could interpret the sign and confirm?
The same rhino logo is of course the logo for both the Stare and Nowe zoo with the rhinos being of course at the Nowe Zoo.