The world's oldest dog has celebrated his 31st birthday, according to Guinness World Records. Bobi, a purebred Rafeiro do Alentejo, was feted during a party on Saturday at his home in the Portuguese village of Conqueiros, where has lived his entire life. More than 100 people attended the “very traditional” Portuguese party, owner Leonel Costa said. Local meats and fish were served to up to 100 guests, with extra for Bobi, who only eats human food. A dance troupe also performed, with Bobi participating in one of their routines. Mr Costa has owned several older dogs in the past, including Bobi’s mother Gira, who lived to age 18. However, Mr Costa said he never imagined any of his dogs would reach their 30s. “We see situations like this as a normal result of the life that they have, but Bobi is one of a kind,” he said. One of the biggest contributing factors to Bobi’s longevity is the “calm, peaceful environment” in which he lives, according to Mr Costa. Throughout his life, Bobi has freely roamed the forests surrounding the Costa house. He has never been chained or leashed. The “very sociable” dog has never been lonely because he grew up surrounded by many other animals, Mr Costa said. Now in his senior years, Bobi finds it difficult to walk, so he prefers to hang out at home in the yard. His eyesight has got worse, meaning he often bumps into things when he walks. Like older humans, Bobi sleeps a lot. He immediately lies down in bed after eating, although on cold days, he chooses to nap by the fire, his owner said. Bobi’s birth date was confirmed by the Veterinary Medical Service of the Municipality of Leiria, with which the dog was registered in 1992. His age has also been verified by a pet database authorised by the Portuguese government. For Mr Costa, now 38, Bobi is a living reminder of the past. “Bobi is special because looking at him is like remembering the people who were part of our family and unfortunately are no longer here, like my father, my brother, or my grandparents who have already left this world,” he said. “Bobi represents those generations.”