Bruce – a dogue de bordeaux cross Rottweiler – has been found tied to a tree, scared and shaking near the RSPCA Ashley Heath Animal Centre.
A member of the public spotted Bruce and contacted the animal welfare charity as there was no sign of an owner around.
It is not understood how Bruce came to be tied to the tree, nor how long he was there.
RSPCA inspector Jo Story said: “Bruce has a microchip but the details are not up to date so we do not know if he has previously been lost, or perhaps even stolen.
“We understand he is 16 months old and was most recently re-homed along with his sister to a woman in Bournemouth around four months ago, however we have been struggling to get in touch with them.
“We’re really keen to hear from anyone who recognises Bruce, knows where he came from, or who knows how he came to be left alone.
“He’s very affectionate and enjoys attention. He is a lovely dog.”
Anyone with information about Bruce is asked to call the RSPCA on 0300 123 8018 and leave a message for Inspector Jo Story.