Fourteen geckos have been found dumped among communal bins in Penarth.
The lizards were discovered inside four plastic boxes by a local resident who was using the bins at Park View Court on Sunday.
The RSPCA says there was no food or water inside the boxes but the geckos were in good condition and were transferred to a local wildlife centre.
RSPCA Inspector Gary Lucas said, "We are trying to find out where these lizards came from and how they came to end up among these bins.
“It is unusual because there was such a large number of them which makes it more likely that someone will have information about where they came from."
Anyone with information is asked to call the RSPCA inspector information line on 0300 123 8018.