The death of Bobi the Portuguese mastiff at 31 was history-making – no dog before had ever reached such a grand old age.
But awe soon turned into scepticism, as vets wondered whether it was biologically possible for a dog to live for the equivalent of 200 human years.
Now, the Guinness World Records has said it is investigating whether the claim the Portuguese mastiff lived to 31 years and 165 days is genuine.
Alongside widespread media coverage of the secrets to Bobi’s longevity, there has been intense scrutiny online of images of Bobi in 1999, in which he has different coloured paws to the dog which died in Portugal on 21 October. Vets have raised other doubts: although his age had been registered on the national pet database, this is usually based on owners’ self-certification. Furthermore, genetic testing he had received merely confirmed he was old, rather than his precise age.
Subsequently, a Guinness World Records spokesperson told the Guardian: “We’re aware of the questions around Bobi’s age and are looking into them.”
Danny Chambers, a vet and council member of the Royal College of Veterinary Surgeons, said of the 18,000 – members of the Veterinary Voices group he runs: “Not a single one of my veterinary colleagues believe Bobi was actually 31 years old.
“This is the equivalent of a human to living to over 200 years old which, given our current medical capabilities, is completely implausible. Extraordinary claims require extraordinary evidence, and no concrete evidence has been provided to prove his age.
“We are a science-based profession, so for the Guinness Book of Records to maintain their credibility and authority in the eyes of the veterinary profession, they really need to publish some irrefutable evidence.”
Chambers added that Bobi’s example had been taken up by anti-pet food zealots “who have long campaigned that dog food is killing pets and that raw feeding is healthier” – since the mastiff lived off human food.
In his practice, he occasionally sees dogs reach their late teenage years, but they tend to be smaller breeds and not overweight, unlike Bobi, which would make it “even more surprising that he happened to live almost three times longer than average”.
Vets often find that owners are unsure of the exact age of their dog, he said, especially if it was rehomed, meaning ages on clinical records can be inaccurate. In some cases, parents replace a dead pet with a new one to prevent their child from getting upset.
However, Andrew Knight, emeritus professor of veterinary welfare, said that throughout history, “there have been some other very old dogs”.
He said it would be helpful to compare Bobi with the five -to-10 other oldest dogs to see how much of an outlier he is, though there would need to be strong evidence to verify the ages of all those dogs for this to be an effective exercise.
Bobi snatched the world’s oldest dog crown from Spike the chihuahua, from Ohio, who died at 23 years and seven days in 2022. The oldest recorded dog was Australia’s Bluey, who died in 1939 at the age of 29 years and five months.
According to Bobi’s owners, the Costa family, there are good genes in his lineage: his mother lived to the age of 18 while another of the family’s dogs died at the age of 22.
Leonel Costa was eight years old when he rescued Bobi from being put down by his parents, who felt they had too many animals. Costa and his brothers kept the dog in secret, until he was discovered and allowed to remain part of the family.
Bobi lived his whole life in the village of Conqueiros, near Portugal’s west coast. Costa credits Bobi’s longevity to his diet and roaming around the “calm, peaceful, environment” without a lead.
Bobi’s owner has been approached for comment.