The upsetting discovery took place on Friday (21 June) at around 11am near the entrance to the nature reserve opposite Renoir Road Play Area, Renoir Road in Newport.
The three black pups of an unknown breed were found by a member of the public in a black shoe box and were wrapped in a blue jumper.
RSPCA Animal Rescue Officer Danielle Wilson said: “These three pups had their umbilical cords still attached, so they couldn’t have been that old at all.
“We don’t know whether they died during birth and someone just didn’t know what to do with the bodies, or they died afterwards.
“We’re making enquiries about CCTV in the area, and I’ve placed a poster at the location in a bid to get information.
“We’re appealing to anyone with any first hand information to give us a call on the RSPCA Inspectorate Appeal line on 0300 123 8018, and can quote 1288099.”
Danielle added: “Whatever has happened here, it is very sad that these pups have died and we’d like to thank the member of the public for looking out for them and sounding the alarm.”
As the RSPCA enters its landmark 200th anniversary year – the charity wants to inspire a one million strong movement for animals, as the charity aims to “create a better world for every animal”.
To find out how you can join our million-strong movement for animals visit www.rspca.org.uk/200
