It was a warm February evening in South Delhi, and I was parked on my motorcycle at the edge of a narrow lane, clipboard in hand, running a stranger approach test on a pair of free-ranging dogs. One jumped onto my lap, tail a blur, licking my face like I was a long‑lost friend. The other rolled onto its back, belly up, nudging my ankle with its nose. I jotted down their scores. Textbook‑friendly animals.
Then I started my bike.
Within seconds, both dogs were sprinting after me, barking furiously, teeth bared in a snarl. One lunged close enough that I felt its breath on my calf. If you had witnessed only that moment; a man on a motorcycle being chased by two snarling dogs, you would have called them dangerous. You might have felt a jolt of fear. You might have later told someone about the “aggressive strays” on that street.
But I had just been sitting with those dogs. Nothing about their temperament had changed. What changed was that I went from being a stationary person to a fast‑moving object.
I am a PhD researcher studying the behaviour of free‑ranging dogs in Delhi, a city that is home to hundreds of thousands of them. Part of my work involves systematically scoring dogs for aggression using standardised behavioural tests, like the stranger approach I was conducting that evening. Over several months of fieldwork, this paradox kept repeating itself: dogs that wagged their tails and solicited petting would, minutes later, tear after my bike with convincing ferocity. It happened not once but multiple times, with different dogs, in different neighbourhoods.
The explanation lies in a distinction that most people, understandably, never think about. Ethologists have long recognised that chasing and aggression are driven by fundamentally different motivational systems. Aggression, in the true behavioural sense, involves a dog that perceives a threat and responds with intent to drive it away or defend itself. It is directed at a specific target for a specific reason: protecting food, guarding pups, responding to a perceived intrusion.
Chasing, on the other hand, belongs to what is called the predatory motor sequence; a hardwired chain of behaviours: orient, eye, stalk, chase. This sequence is triggered not by threat, but by movement. A bicycle whizzing past, a jogger’s pumping legs, a car’s spinning tyres—these are stimuli that activate a deep, reflexive response in the dog’s brain. The dog is not deciding to attack. It is reacting to motion the way a cat pounces on a darting string. The trigger is kinetic, not emotional.
What makes this even more interesting is the inconsistency of the behaviour. Not every dog chases. And even a dog that chased me one evening would sometimes let me ride past unbothered on another day. This variability is itself a clue. If chasing were an expression of genuine hostility, you would expect it to be more reliable. A truly aggressive dog tends to be aggressive across situations. But chasing depends on context: how close to their core resting spot the dogs are, whether they are alone or in a group, how alert or aroused they already happen to be, and how fast and how close the moving stimulus passes.
Group dynamics play a particularly powerful role. A lone dog resting by a wall may barely lift its head as you ride past. But add two or three companions, and the calculus changes. One dog reacts, and the others follow; a phenomenon called social facilitation. The chase becomes a collective event, louder and more dramatic than any single dog would have produced alone. To the person on the receiving end, it looks like a coordinated attack. In reality, it is closer to a chain reaction.
Habituation matters too. Dogs living along busy arterial roads, where hundreds of vehicles pass every hour, tend to ignore traffic entirely. They have learned, through sheer repetition, that moving vehicles are part of the background. But dogs in quieter residential lanes, where a motorcycle is an occasional disruption, remain reactive. The stimulus is still novel enough to trigger the chase.
Why does any of this matter beyond the world of animal behaviour research? Because the perception of aggression has real consequences for these animals, and those consequences have recently become more severe. In August 2025, the Supreme Court of India took suo motu cognisance of rising dog bite incidents and issued a series of directives on the management of free‑ranging dogs across the country. While the court’s modified order of August 22 reaffirmed the Animal Birth Control framework, requiring dogs to be sterilised, vaccinated, and released back to their original locations—it carved out a crucial exception: dogs found to be rabid or “dangerously aggressive” may be permanently quarantined or kept in shelters, and not returned to the streets.
The word “aggressive” in that directive is doing enormous work, and it is precisely where the problem lies. Who decides what counts as aggressive? If a resident sees a dog chasing a cyclist and files a complaint, that dog may well be classified as aggressive and permanently removed from its territory. But as my fieldwork has shown, the very same dog might score as friendly and sociable when tested in a stationary interaction. We could, in effect, be condemning perfectly healthy, well‑adjusted dogs to a life in an overcrowded shelter, or worse—simply because they chased a moving vehicle. The directive is well‑intentioned, but without a scientifically grounded understanding of what aggression actually looks like in dogs, it risks being applied to behaviours that are not aggression at all.
This is not merely an academic concern. It is, in fact, one of the central objectives of my doctoral research: to map aggression levels in free‑ranging dogs across Delhi using the stranger approach test, identifying where true aggression hotspots exist and, just as importantly, where they do not. If this data can show that the neighbourhoods people perceive as having “aggressive” dogs are actually home to sociable animals whose only offence is chasing passing vehicles, it gives municipalities and animal welfare bodies a more honest picture of which areas genuinely need intervention, and which do not. This does not mean that chasing is without consequence. A person startled by a pursuing dog can swerve, fall, or panic, especially on a busy road. The behaviour carries real risks, and those risks deserve practical responses, but the responses should be proportionate to the actual nature of the problem, not inflated by a misunderstanding of what the dog is doing and why.
The next time a street dog chases you, consider the possibility that the animal hurtling towards you with bared teeth was, moments ago, napping peacefully or begging for scraps from a shopkeeper. It has not decided to attack you. You simply moved through its world a little too quickly, and something ancient and reflexive switched on. Understanding that difference will not make the experience less startling. But in a country where millions of free‑ranging dogs depend on the thin line between tolerance and persecution, it could mean the difference between a dog being returned to its territory and one being consigned to a shelter for no reason other than a reflex older than the species itself.
Arshyaan Shahid is a wildlife biologist currently investigating human-dog conflict in Delhi
Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth