Slip Leads: Useful Tool or Training Shortcut? What the Evidence Actually Tells Us
I own slip leads. I also don't use them to teach dogs not to pull.
Those two statements aren't contradictory.
Slip leads can be incredibly useful pieces of equipment.
They're quick. They're simple. They don't rely on an existing collar being secure. They have legitimate applications in working-dog handling, rescue, temporary restraint and emergency situations.
My problem isn't the existence of a loop of rope.
It's what happens when tightening that loop around a dog's neck becomes the lesson.
And perhaps the most useful question we can ask about any piece of dog-training equipment isn't:
“Is this tool good or bad?”
It's:
What function is this equipment performing here?
Because the same slip lead can function as a temporary safety device in one situation and as an aversive behaviour-modification tool in another.
Those aren't the same thing.
What actually is a slip lead?
A slip lead combines a collar and lead into one piece of equipment.
One end passes through a loop to form a larger loop around the dog's neck. Unlike a conventional fixed collar, that loop can become smaller when tension is applied and loosen when tension disappears.
That gives the slip lead one very obvious practical advantage:
speed.
There is no buckle to fasten or D-ring to find.
Put it over the dog's head and the dog is attached.
That helps explain why slip leads have become established in several specialist contexts.
Temporary restraint
If somebody needs to secure an unfamiliar loose dog, they may have no idea whether the dog's existing collar fits properly, whether its buckle is secure or whether the dog can reverse straight out of it.
A slip lead can provide immediate restraint without relying upon that equipment.
Kennel, rescue and dog-control situations
For similar reasons, slip leads can be useful for briefly moving suitable dogs from one secure area to another.
Working gundogs
They also make practical sense in working situations where a dog may repeatedly transition between being restrained and working freely.
A retriever may need to be held, released to retrieve, return, move again and subsequently be released.
A lightweight lead that can be removed and replaced rapidly has an obvious practical advantage.
None of that is particularly controversial.
But notice the function in all of those examples.
The lead is primarily being used for:
management, safety or temporary restraint.
That's quite different from deliberately using the tightening action to change behaviour.
A slip lead isn't automatically an aversive training tool
This distinction matters.
Imagine a trained dog walking next to somebody on a completely loose slip lead.
There is virtually no tension.
The dog walks twenty metres from a vehicle to a secure working area.
The lead comes off.
The dog may have experienced little meaningful constriction at all.
Now imagine another dog.
The dog moves forwards.
The lead tightens.
The dog slows.
The pressure disappears.
The dog moves forwards again.
The lead tightens again.
Eventually the dog learns to modify their movement to avoid or terminate the pressure.
Same piece of equipment.
Different function.
If pressure is applied and a behaviour causes that pressure to stop, and that behaviour subsequently becomes more likely, we can describe that contingency as negative reinforcement.
If a lead correction is applied following a behaviour and that behaviour subsequently becomes less likely, the correction has functioned as positive punishment.
Those terms aren't moral judgements.
They're descriptions of learning contingencies.
Which means saying:
“It's just communication.”
doesn't really answer the question.
Of course pressure can communicate information.
But we can still ask:
What made the dog's behaviour change?
If the answer is:
“The dog learnt that doing X makes the pressure stop,”
then pressure isn't merely carrying information.
Its removal is reinforcing behaviour.
But surely a little pressure around the neck isn't harmful?
This is where we actually have some useful research.
In 2020, Carter, McNally and Roshier investigated pressures generated by seven different collars and a slip lead.
Importantly, they didn't deliberately expose living dogs to potentially injurious forces. They created a simulated canine neck fitted with pressure sensors.
They then applied forces representing:
a firm pull;
a strong pull;
and a jerk.
Measured pressures across the different collar types and forces ranged from 83 kPa to 832 kPa.
Both the equipment used and the force applied significantly influenced the pressure exerted on the simulated neck.
And their conclusion is important:
none of the collars they tested produced pressure sufficiently low to eliminate the potential risk of injury when pulling occurred.
That doesn't mean:
“Every dog wearing a slip lead will suffer a neck injury.”
It doesn't even mean that flat collars are inherently safe while slip leads are inherently dangerous.
The research actually gives us a more useful message:
The neck isn't an ideal place to repeatedly absorb significant lead forces.
And with a slip lead we have the additional characteristic that the loop itself can reduce in circumference as tension occurs.
That makes me particularly cautious about using one on dogs who regularly:
pull;
lunge;
hit the end of the lead;
react strongly;
receive lead corrections;
or spend significant portions of their walk under tension.
Neck pressure doesn't necessarily affect only the neck
Another interesting study looked at intraocular pressure — pressure inside the eye.
Pauli and colleagues measured the force individual dogs generated while pulling and then compared what happened when equivalent pressure was applied through a neck collar versus a harness.
Pressure applied through the collar produced a significant increase in intraocular pressure.
The harness did not produce the same effect.
The researchers therefore recommended harnesses particularly for dogs where increased intraocular pressure could be problematic.
Again, let's be careful with what that means.
It does not demonstrate that:
“Slip leads damage dogs' eyes.”
But it does demonstrate something important:
Mechanical pressure around the neck can have physiological effects beyond the skin directly underneath the equipment.
That's worth considering when choosing where we want lead forces to be distributed.
What about all the other health claims?
Search online and you'll find claims that slip leads cause:
thyroid disease, vagus-nerve damage, cervical subluxation, collapsed tracheas, laryngeal paralysis, spinal damage and numerous other conditions.
Some mechanisms may be biologically plausible under particular circumstances.
But that isn't the same thing as having evidence that ordinary slip-lead use causes those diseases.
I haven't found sufficiently good evidence to make those claims.
And we don't need to.
There are already legitimate questions about pressure, comfort, learning and welfare without turning plausible mechanisms into proven diagnoses.
Evidence-based practice also means being willing to say what the evidence doesn't demonstrate.
“But my dog doesn't pull.”
Then we're talking about a rather different situation.
If a trained dog genuinely travels on a loose slip lead and rarely produces tension, the argument about repeated constriction becomes considerably weaker.
Equipment doesn't exist independently of the behaviour occurring around it.
But this raises an interesting question.
If a slip lead is harmless because your dog never pulls, why are slip leads so often recommended specifically for dogs who do?
That's where the argument starts to change.
If we're choosing the equipment precisely because its tightening action makes pulling less successful or comfortable, then its constricting property isn't incidental anymore.
It's part of the training contingency.
“But I barely use any pressure.”
Perhaps.
But the amount of visible handler effort doesn't necessarily tell us how salient the sensation is to the dog.
This becomes particularly interesting when slip leads are positioned high on the neck, immediately behind the ears.
One argument for this position is that relatively small movements provide greater control over the dog's head.
But if very small amounts of force in a particular location produce substantial behavioural changes, we still need to ask why.
Less visible handler effort doesn't automatically equal a less aversive experience for the dog.
We currently don't have good experimental evidence allowing us to assign a precise subjective experience to different positions of a slip lead.
So I wouldn't claim:
“High placement definitely hurts more.”
But equally, “I'm hardly applying any force” isn't evidence that the dog experiences nothing significant.
Does pressure-and-release work?
Yes.
This is another area where dog-training conversations can become unnecessarily polarised.
Punishment can reduce behaviour.
Negative reinforcement can increase behaviour.
If they couldn't, they wouldn't be recognised learning processes.
So:
“But it works.”
isn't really the interesting question.
The more useful questions are:
What did the dog learn?
What emotional experience accompanied that learning?
What other behaviours might also have been affected?
And could we achieve the behaviour we want without relying upon an unpleasant consequence?
Research comparing companion dogs trained predominantly using reward-based versus aversive-based methods gives us good reason to take those questions seriously.
Dogs exposed to higher proportions of aversive training have been observed displaying more stress-related behaviour, more tense behavioural states, increased post-training cortisol and, in one study, more pessimistic responses during a later cognitive-bias task.
That doesn't demonstrate that every moment of pressure from a lead causes psychological harm.
But it does challenge the idea that we should choose aversive contingencies simply because they can suppress behaviour.
What happens with a reactive dog?
This is where I become particularly cautious about constriction-based equipment.
Imagine a dog who is worried by unfamiliar dogs.
Another dog appears.
Our dog looks.
Their arousal rises.
They move forwards.
The slip lead tightens.
Perhaps the handler pulls them backwards.
The other dog disappears.
Next walk:
Dog appears.
Arousal.
Neck pressure.
Restraint.
Dog appears.
Arousal.
Neck pressure.
Restraint.
We shouldn't leap from that sequence to:
“Slip leads cause reactivity.”
There isn't evidence supporting such a simple causal claim.
But from a learning perspective, I still have a very reasonable question:
Do I want an unpleasant or highly salient physical sensation repeatedly occurring in close temporal association with the very stimulus I'm trying to change the dog's emotional response towards?
For me, particularly when working with fearful, anxious or reactive dogs, the answer is no.
I'd rather create distance, alter the environment, work below threshold where possible, reinforce useful responses and change the dog's experience of the trigger.
Restraint can matter even without pain
There is another part of this discussion that can get lost when everybody argues about whether a slip lead “hurts.”
Imagine a dog sees something they desperately want to investigate.
Their motivation says:
GO.
The lead says:
STOP.
The dog tries harder.
Restraint increases.
They try harder again.
Now we may have:
motivation → blocked access → increased effort → increased restraint → frustration.
That matters particularly for dogs already prone to frustration-related behaviour such as:
barking;
lunging;
jumping;
spinning;
lead grabbing;
or redirected mouthing.
Sometimes the question isn't:
“How do I make this dog stop fighting the lead?”
It's:
“What is the dog trying to do, why is it important to them, and what is our restraint doing to their emotional state?”
And now we need to talk about group dog walks
This is one of my biggest concerns about the routine use of slip leads.
Picture one professional walker with several dogs.
One dog catches a scent and slows down.
Another keeps moving.
One wants to investigate the verge.
Another spots a dog across the road.
A third stops.
Two accelerate.
The walker needs everybody moving in roughly the same direction.
These dogs aren't necessarily “pulling badly.”
They're simply behaving as different individual dogs.
And this matters because real-world leash-tension research demonstrates that tension isn't something generated exclusively by naughty dogs pulling forwards.
Forces occur at both ends of the lead.
Researchers using a leash-tension meter were able to distinguish pulling events initiated by dogs from those initiated by handlers.
Young dogs pulled more frequently. Larger dogs produced greater tension. Handler forces also contributed substantially to the interaction.
So consider what happens when several dogs attached by slip leads need to move as one unit.
One dog wants to sniff.
The group continues.
Tension.
One dog pauses.
The group continues.
Tension.
One dog moves sideways.
The handler continues forwards.
Tension.
One dog becomes excited and accelerates.
The handler restrains them.
Tension.
Another dog responds to that dog's movement.
More movement.
More restraint.
And because the attachment is a slip lead, those forces are transmitted through a loop capable of tightening around the neck.
This is different from deliberately jerking a dog's lead.
But from the dog's body, force is still force.
“But they're under control.”
They may well be.
But I think we need to separate two questions:
Can I control these dogs?
and
Are these dogs experiencing a good walk?
Those aren't automatically the same thing.
Walking isn't simply transportation from A to B.
Dogs gather enormous amounts of information through olfaction.
They stop.
Investigate.
Backtrack.
Change pace.
Move laterally.
Follow scent.
Pause.
Choose.
Research into nosework has found that giving dogs opportunities to use olfaction and make active choices can contribute positively to welfare and has produced more optimistic responses in cognitive-bias testing.
That doesn't prove that preventing a dog from sniffing causes poor welfare.
But it certainly gives us reason to treat olfactory exploration and agency as meaningful, rather than inconveniences that need controlling.
So if one dog wants to spend thirty seconds investigating a scent while five others are required to continue walking, something has to give.
Perhaps the group waits.
Perhaps the dog abandons the sniff.
Perhaps the handler applies tension.
Perhaps the other dogs create tension through their movement.
And that's where the equipment matters.
The group itself can change the dog's behaviour
There's another layer.
Dogs don't move through the world independently of one another.
One dog suddenly orientating can cause others to orient.
One accelerating can affect everybody else's movement.
Excitement can spread through a group.
So the amount of physical control needed to keep several dogs travelling together may change dynamically throughout the walk.
That doesn't mean group dog walking is inherently bad.
Nor does it mean every professional dog walker using a slip lead is harming dogs.
But I think it creates an important welfare question:
If the walking system requires repeated neck pressure whenever an individual dog deviates from the movement of the group, is that the equipment we want to use?
And perhaps an even bigger question:
How much individual choice can each dog actually have when several dogs are required to move as one unit?
What about gundogs?
This is probably the most reasonable challenge to criticism of slip leads.
Working gundog handlers have practical reasons for using them.
A trained retriever may spend relatively little time restrained.
The lead may remain completely loose.
It needs to come off quickly when the dog is sent to work.
Bulky equipment may be unnecessary.
Fine.
But:
“This equipment is extremely convenient for this specialised working context”
doesn't establish:
“This is therefore the best equipment for an adolescent pet Labrador pulling around an housing estate for 45 minutes.”
Those are completely different jobs.
Equipment should be assessed according to what it is doing in that particular context, not according to the tradition attached to it.
Slip leads can also provide a genuine safety advantage
There are circumstances where a dog simply needs securing immediately.
An unfamiliar stray.
A newly transported dog.
A dog whose existing collar can't be trusted.
A temporary transfer between secure locations.
In those circumstances, the ability to place a lead directly around the dog without relying on their existing equipment can be extremely useful.
Again:
function matters.
Using a slip lead for thirty seconds to prevent an unknown dog escaping isn't equivalent to using repeated neck pressure to teach heelwork.
We don't improve animal welfare by pretending those situations are identical.
Harnesses aren't magically harmless either
This article isn't an argument for:
SLIP LEAD BAD. HARNESS GOOD.
A badly fitted harness can rub, rotate, restrict movement, be escaped from or be extremely unpleasant for a dog who finds equipment handling difficult.
Harness design and fit matter.
So does the individual dog.
My preference is to choose equipment that:
keeps the dog and human safe, minimises unnecessary pressure, permits comfortable movement and doesn't need to function as the primary behaviour-change mechanism.
Then we teach the behaviour separately.
So when is a slip lead a problem?
I find it useful to think about three broad functions.
🟢 MANAGEMENT
Loose dog found somewhere unsafe.
Slip lead on.
Dog secured.
Dog moved somewhere safe.
Lead removed.
The purpose is temporary restraint and safety.
🟠 SAFETY OR SPECIALIST HANDLING
A trained working dog travelling briefly on a loose slip lead.
Temporary handling or transfer.
An unusual situation where rapid attachment/removal has a genuine practical advantage.
The constricting action isn't deliberately being used to modify behaviour.
Context matters.
🔴 BEHAVIOUR MODIFICATION
Dog pulls.
Lead tightens.
Dog slows.
Pressure disappears.
Or:
Dog reacts.
Handler applies a correction.
Reaction stops.
Or:
Dog repeatedly attempts to move away from the handler's preferred position and neck pressure is used to keep them there.
Now the tightening isn't incidental.
It's part of the contingency changing behaviour.
And that's where I think we should ask whether we can do better.
So what should we do with dogs who pull?
Teach them.
Loose-lead walking isn't something dogs arrive knowing.
Human walking is actually rather strange from a dog's perspective.
We want an animal with a different natural pace, extraordinary olfactory abilities and plenty of reasons to investigate their environment to travel at our speed, in our direction, within approximately two metres of us.
That's a considerable learned skill.
So let's teach:
orientation to the handler;
reinforcement around the position we want;
moving together;
changes of direction;
slowing and stopping;
responding to lead information without requiring force;
environmental rewards;
opportunities to sniff;
appropriate access to things the dog values;
and gradually working around increasing distractions.
And let's make sure the dog also gets walks where walking nicely isn't the entire point.
Sniff.
Explore.
Move.
Investigate.
Be a dog.
The question I want us to start asking
Perhaps we've spent too long arguing about whether particular pieces of equipment are inherently “good” or “bad.”
I think there's a better question.
Next time you see a slip lead — or indeed any training equipment — ask:
What function is this equipment performing here?
Is it simply keeping the dog safe?
Is it temporary management?
Is it specialist equipment being used loosely by a dog already trained for the situation?
Or:
Does something uncomfortable happen when the dog makes the “wrong” choice?
Because if the dog's behaviour changes primarily because pulling makes something tighten around their neck, the lead hasn't magically taught loose-lead walking.
The consequence has changed the behaviour.
And yes, that may work.
But “does it work?” shouldn't be the end of our welfare conversation.
We can ask something better:
What is the dog learning?
What are they experiencing while learning it?
What other associations might we be creating?
What opportunities for normal behaviour are being lost?
And:
Could I teach this another way?
For me, in everyday dog training, the answer to that last question is overwhelmingly:
Yes.
References and further reading
Carter, A., McNally, D. & Roshier, A. (2020). Canine collars: an investigation of collar type and the forces applied to a simulated neck model. Veterinary Record, 187, e52.
Pauli, A.M., Bentley, E., Diehl, K.A. & Miller, P.E. (2006). Effects of the application of neck pressure by a collar or harness on intraocular pressure in dogs. Journal of the American Animal Hospital Association, 42(3), 207–211.
Shih, H-Y. et al. (2020). Behavioural Evaluation of a Leash Tension Meter Which Measures Pull Direction and Force during Human–Dog On-Leash Walks. Animals, 10(8), 1382.
Vieira de Castro, A.C. et al. (2020). Does training method matter? Evidence for the negative impact of aversive-based methods on companion dog welfare. PLOS ONE, 15(12), e0225023.
Duranton, C. & Horowitz, A. (2019). Let me sniff! Nosework induces positive judgment bias in pet dogs. Applied Animal Behaviour Science, 211, 61–66.
American Veterinary Society of Animal Behavior. Humane Dog Training Position Statement.
