The world’s oldest dog recently marked its 31st birthday, making it the most senior known dog alive, according to the Guinness Book of World Records,

Bobi, a purebred Rafeiro do Alentejo, a breed of Portuguese dog, celebrated during a party Saturday at his home in the rural Portuguese village of Conqueiros, where he has lived his entire life.

Over 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.

Costa has owned several old-aged dogs, including Bobi’s mother, Gira, who lived to the age of 18. However, Costa said he never imagined his dogs would reach their 30s.

"We see situations like this as a normal result of their life, but Bobi is one of a kind," Costa said.

One of the most significant contributing factors to Bobi’s longevity is the "calm, peaceful environment" in which he lives, according to 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 was never lonely because he grew up surrounded by many other animals, Costa said.

Now in his senior years, Bobi finds walking difficult, so he prefers to hang out at home in the yard. His eyesight has worsened, meaning he often bumps into things when walking. Just like old-aged humans, Bobi sleeps a lot. He immediately lies in bed after eating, although his owner said he chooses to nap by the fire on cold days.

Serviço Medico-Veterinário has confirmed Bobi’s birth date do Município de Leiria (Veterinary Medical Service of the Municipality of Leiria), which registered Bobi in 1992.

His age also has been verified by SIAC, a pet database authorized by the Portuguese government and managed by the SNMV (Sindicato Nacional dos Médicos Veterinários; National Union of Veterinarians).

Costa, now 38, was just eight years old when Bobi was born. For him, Bobi is a living reminder of the past, he said.

"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, brother, or grandparents who have already left this world," Costa said. "Bobi represents those generations."