‘Heat wave makes dogs aggressive’

The report of a dog attacking and killing the owner’s child in Wakiso District on Monday has sparked debate on the impact of climate change, in this case the ongoing heat wave, on the behaviour of animals following separate findings by American researchers that more dog bites occur during hotter seasons.

Whereas Ugandan veterinarians and dog breeders said they had no independent study of similar outcome in the country, America’s Harvard Medical School researchers concluded that “the rates of dogs biting humans increases with increasing temperature and ozone”.

They write in their 2023 study report that “we also observed that higher Ultraviolet (UV) irradiation levels were related to higher rates of dog bites”. 

“We conclude that dogs, or the interactions between humans and dogs, are more hostile on hot, sunny, and smoggy days, indicating that the societal burden of extreme heat and air pollution also includes the costs of animal aggression,” the report reads.

Uganda, just like its neighbour South Sudan, which shut schools over heatwaves, is experiencing a higher-than-normal temperature of above 30 degree Celsius. The northern part is hotter, while daily temperatures in Kampala, the capital, oscillate between 28 and 35 degrees Celsius.

The Intergovernmental Authority on Development (Igad) meteorological unit in its temperature forecast this month, indicates that Uganda could continue to experience “warmer than usual conditions”.

For the heat stress index, Igad’s Climate Prediction and Applications Centre (ICPAC) data for the week running from yesterday to March 26, shows that most areas in West Nile, some parts of northern and southern Uganda, and some spots in eastern and southwestern Uganda, are falling in extreme caution zones (heat exhaustion).

Most parts of the country, however, are in the caution zone (heat fatigue with prolonged exposure) with only a few spots in Kisoro and Kabale expected to be free from heat stress.

In their 2023 study titled “The risk of being bitten by a dog is higher on hot, sunny, and smoggy days”, the Harvard University researchers who analysed public records in their study published in scientific journal, Nature, reported 69,525 dog bites of humans in the period.

They said they were not certain how the temperatures could be influencing the number of dog bites, but that evidence exists that heat stress can cause cognitive breakdown in rats. They suggested the same could also apply to dogs.

“The present findings expand the association between temperature, air pollutants and aggression across species to also include dogs. It is notable that in rodents, exposure to ozone, heat stress, and their combination induces cognitive decline and neuroinflammation,” the report reads.

The researchers reiterated established facts that dogs bite primarily as a reaction to something, such as “stressful situations, a scare, startle, or threat, or to protect food, toys or their puppies”.

“Dogs might bite defensively or to be left alone. In our analysis, it is unclear if dog behaviour is directly altered by ozone and heat, or, if the observed increase in dog bites is a consequence of altered behaviour imposed by the human victim and/or the dog’s master, which in many cases are the same individual,” the researcher noted.

Some of the scientists and dog breeders who spoke to our reporter were not sure whether a possible link between heat stress and dog aggression exists. This reporter could also not find a related study in Uganda.

“The heat stress can make them stubborn, but not that much aggressive,” said Mr Jessy Muwakanya, a dog breeder and trainer from Roar Dog Breeders and Trainers in Seguku off Entebbe Road.

Ms Nada Andersen, the chairperson of Canine Association Uganda, advised people owning dogs to allow them to move out of the kennel (dog house) and interact with the family members regularly so that the dogs can familiarise with them. 

“A dog needs to familiarise itself with its compound. Because if you keep the dog in the house locked all the time, the dog will guard [its] house because [its] not a part of your house; so, [it] doesn’t care. [It] will only react when [it’s] threatened around [its] house,” she said.

Linking the findings in the Harvard study with the incident in Wakiso, Dr Daniel Kasibule, the president of the Uganda Veterinary Association, said heat stress might not be the major contributor to animal aggression.

“Dogs have heat regulatory mechanisms. When they pant with their tongue out, the tongue has got a cooling effect, they can survive in hot weather; so, I wouldn’t think heat stress can spur such wild behaviour,” he said.

He added: “Dog owners should be careful with dogs, know their normal behavioural patterns, observe the recommended animal welfare rights – provision of food, water, exemption from suffering and freedom to move and health. Many people are keeping dogs without knowing what to do. Some people are keeping dogs because of class without knowing different aspects of the dog.”

According to Dr Kasibule, some breeds of dogs such as Rottweilers, which allegedly attacked and killed a child in Wakiso on Monday, are inherently aggressive.