Global warming is fuelling an alarming rise in dog attacks, according to new research.
The risk of being bitten increases by up to 11 per cent on sunny or smoggy days, scientists say.
High temperatures and air pollution has previously been linked to aggression in humans, monkeys, rats and mice.
Now a study spanning 10 years has found the phenomenon also applies to man's best friend.
Last year, there were nearly 22,000 cases of out-of-control dogs causing injury in the UK.
In 2018, there were just over 16,000.
Four fatal attacks have already happened in 2023 - a dog walker mauled to death, a four-year-old girl killed in her back garden, a 37 year old man mauled to death and earlier this month a woman in her 70s.
And just this week, Darren Pritchard was jailed for owning two out of control dogs that killed grandmother Lucille Downer as she sat in her back garden.
Last year saw a record 10 dog-related deaths in the UK.
Lead author Dr Clas Linnman, of Harvard Medical School, Boston, said: "We conclude that dogs, or the interactions between humans and dogs, are more hostile on hot, sunny, and smoggy days."
The issue has been largely overlooked in the debate on climate change.
Animal-related injuries lead to health care costs of more than $1 billion a year in the US - and they are becoming more frequent.
Dr Linman said: "It indicates the societal burden of extreme heat and air pollution also includes the costs of animal aggression."
In January dog walker Natasha Johnston, 28, was mauled to death in Caterham.
Less than three weeks later four-year-old Alice Stones was killed in a back garden in Milton Keynes.
Last month Jonathan Hogg, 37 died in Manchester after looking after a friend's dog that turned on him and on June 3, a pensioner aged 70 was killed.
Dr Linnman and colleagues analysed almost 70,000 reported dog bites in eight cities across the States - Dallas, Houston, Baltimore, Baton Rouge, Chicago, Louisville, Los Angeles and New York City.
The data from 2009 to 2018 was either drawn from publicly available records of animal control authorities or or scientific compilations.
There were an average of three bites a day over ten years - enabling associations to be made with weather and pollution.
The study showed cases went up 11, four and three percent on days with higher UV (ultraviolet radiation), temperature and ozone levels, respectively.
On the other hand, there was a slight fall of one percent on days with more rainfall.
Dr Linnman said: "We find the rates of dogs biting humans increases with increasing temperature and ozone.
"We also observed higher UV irradiation levels were related to higher rats of dog bites."
The study in Scientific Reports mirrors a similar trend identified in people.
Dr Linnman said: "Humans commit more violent crimes when temperature and air pollution is higher."
He added: "The findings appear to expand the association between higher temperatures and levels of air pollution and aggression across species to include dogs."
They could open the door to reducing the tens of millions of injuries suffered each year.
They are a public health concern, often leading to physical and psychological trauma in patients, especially childrem.
Most wounds occur to the hands, arms or face and can usually be treated at home, as long as there is no infection which can require emergency hospital care.
In England, recent research found there were 15 dog bites per 100,000 people in 2018 - compared to around five in 1998.
The dog population has increased, but not enough to account for that huge jump - which means dogs are biting humans more than they used to. It's adults in particular where the change is seen.
Dr Linnman called for more research to explore the relationship between dog aggression and the weather.
Records did not include information about other factors that can affect an individual dog's risk of biting such as breed, sex or whether it had been neutered or spayed.
Additionally, no information about prior interactions between the dog and the bite victim, such as whether the individual was familiar with the dog, were available.
Added Dr Linnman: "It is notable that in rodents, exposure to ozone, heat stress, and their combination induces cognitive decline and neuroinflammation.
"The link between ozone and aggression awaits verification such as by randomised double blinded exposure experiments in animals or possibly humans.
"While cardiovascular and pulmonary health effects of pollution are well established, the present results emphases the impacts on behaviour and mental health.
"Through such mechanism, air pollutants and extreme heat could contribute to higher societal and individual burdens then currently appreciated."
