The Portuguese Water Dog or Cao D'Agua to give them their correct name was at a True working dog.
Bred and nurtured by the fishermen of the Algarve to work alongside the crew in fishing boats. The dogs were used to retrieve from the water, drag the nets, carry messages from boat to boat and from shore to boat. The dog was also the guard for the boats when on shore.
The heritage of the breed lives on in the form of water trials and working along side lifeguards in different countries.