Your Rescue Dog Was Easier the First Week

For two weeks you had the easiest dog in the world. He slept in the same corner of the kitchen, took treats like he was afraid of your fingers, and walked the whole block with the leash hanging slack. Your sister met him and said you got lucky.

Then somewhere in the third week he started barking at the man who brings the packages. On Tuesday he hauled you half a block after a squirrel. Yesterday he curled his lip when you reached for his back paw, and you sat down on the kitchen floor and wondered what you had done wrong, or what the shelter had not told you.

Probably neither.

Think about the first night you ever spent in someone else’s house. You did not put your feet on the coffee table. You said nothing about the thermostat. You ate what was for dinner and said it was great. None of that was your personality. It was a guest who did not know the rules yet, moving carefully until he did.

Is this normal?

Most of the time, and two different kinds of evidence point the same way.

The first comes from his body. Researchers at Utrecht University tracked cortisol in the hair of 52 shelter dogs, from the day they arrived through six months after adoption (van der Laan et al., 2022).

Hair cortisol works something like tree rings. It does not record a bad afternoon. It records weeks.

Six weeks of shelter life raised those levels by about a third. After adoption they came down again, back toward where they had started, and the readings that caught it were taken at six weeks and six months in the new home. Not six days.

So the dog who walked through your door was carrying something, and by that first reading his body had set it down. His behavior takes longer.

The second comes from watching what dogs do. A team at Ohio State followed 99 adopted dogs for six months, checking in with their owners four times along the way (Bohland et al., 2023). They were testing what adopters and shelter staff have said for years: that a new dog has a honeymoon period, and does not show you everything he is until he gets comfortable.

Those dogs were adopted between late 2020 and the middle of 2021, which was a strange stretch to be a dog at home with people. Take the direction of what follows rather than the size of it.

The lines they found run in both directions. Excitability climbed over those six months, and so did difficulty in training, sensitivity to being handled for nails and baths, chasing squirrels, and what the questionnaire scores as stranger-directed aggression.

Separation-related behavior went the other way. So did the attachment score, which includes following you from room to room.

Read as a whole, that is a guest who has stopped behaving like one.

How long does this take?

Longer than you have been told, and that is the more useful half of the answer.

Researchers at the University of Lincoln asked 27 adopters how long it took. Fewer than a third said their dog had settled inside three months. One in five said their dog still had not settled at all when they were interviewed, at least three months after adoption (Moyer et al., 2025).

Twenty-seven interviews is a small study, and it records what owners felt rather than what anyone measured. One detail matters here: when a participant gave a range, the researchers filed that dog under the shortest end of it. If that choice moved the numbers at all, it made them shorter, not longer.

The behavior data agrees about the timing. In the Ohio study, the drop in separation-related behavior came between month three and month six. So if you are at week six and he still frets a little when you leave, you have not missed a window.

The drop was small, though. What the authors describe is a high proportion of adopted dogs showing separation-related behavior, with some of them improving.

When it isn’t just settling in

Two things tell you, and neither is how loudly he complains.

Timing. Separation distress arrives fast, often inside the first ten to fifteen minutes after you walk out (Horwitz, 2008). A dog who is quiet for an hour and then starts up when the recycling truck pulls in is telling you about the recycling truck.

Direction. When it is settling in, the trouble around your leaving eases slowly, and in the Ohio data mostly after month three. Panic is different. If he panics every time you leave, or the trouble is getting worse, stop waiting for it to pass and call your vet. Each panicked afternoon can teach him that being alone was worth panicking about.

There is one more line to draw inside all of this. Barking at the mail carrier and growling when a visitor reaches for him are not the same event. The first is a dog with opinions. The second goes to your vet first, in the week it starts, and then to a professional. Do not wait to see whether he grows out of it.

For scale: in a survey of more than 13,700 pet dogs, about 5% had separation anxiety with signs often or very often, a stricter line than earlier studies drew (Salonen et al., 2020). A great many adopted dogs have a hard few months. Far fewer are in the kind of distress that needs a treatment plan.

If you cannot tell which one you have, dog anxiety symptoms when left alone goes through the tells one at a time, and signs of anxiety in dogs covers what worry looks like in an animal who cannot say so. When it is separation anxiety, our full guide has the protocol, and if you would rather follow something built by a professional, we compared the online programs worth considering.

What to do this week

Start at the top. The first two cost you nothing but consistency.

1. Keep the day the same shape, including the days you could sleep in.

Wake him within about half an hour of the same time. Meals at fixed hours. The walk at the same point in the day. A Saturday that looks like a Tuesday. He is reading the pattern, not the clock.

The evidence here is professional experience rather than a trial, and research on routine itself in dogs is thin. What it looks like hour by hour is in our calming routine guide.

2. Walk him before you leave, not after you get home.

The ASPCA suggests exercising your dog right before you leave him alone. A dog who has already been out has somewhere for the morning to go. Exercise in general has some research behind it: in a large Finnish survey, dogs whose owners said they had separation anxiety got less daily exercise, and exercise was the environmental factor most closely tied to it (Tiira & Lohi, 2015). That is an association, and an anxious dog may simply get walked less.

Let him sniff. The walk is for him, so let it be slow and let him choose where his nose goes. What exercise fixes and what it does not is in exercise and dog anxiety.

3. Practice leaving, in doses he can handle.

This is the one that changes things, and most people get it wrong by starting too big.

Find his number first. Step outside, shut the door, count to thirty, come back in. If he stayed calm the whole time, thirty seconds is your starting point. If he did not, your starting point is smaller: the door closing and opening again, with you never leaving the step.

From there, several short departures across the day beat one long one, and the shortness is the whole method. Keep each absence shorter than the time it takes him to get upset. That is the ASPCA’s main rule, and it means you come back while he is still relaxed, never after he has started up. If he panics every time you go, work on this with your vet and a professional, not on your own.

Add a couple of minutes every second or third day, and when he reacts, go back to the last length that worked rather than pushing through it. That is the difference between desensitization, which the American Veterinary Society of Animal Behavior (AVSAB) describes as gradual exposure that keeps the dog feeling safe, and flooding, which it lists among the techniques to avoid.

4. Let people ignore him.

The instinct is to introduce him to everybody so he learns that people are fine. In the Ohio study, stranger-directed aggression was among the scores that climbed across the first six months, and walking a wary dog through a crowd of new hands is flooding by another name.

Ask visitors to sit down and talk to you instead. No reaching, no eye contact, no treats held out at arm’s length. He comes over when he comes over, or he does not, and either is fine this month. A growl is different: call your vet this week. For the fuller protocol once this becomes a lasting pattern rather than settling in, see our guide to a dog who’s afraid of strangers.

5. Say goodbye like a person.

You may have been told to ignore him on the way out and again on the way in. In a study of newly adopted adult dogs, lively hellos and goodbyes did not seem to cause more separation problems than calmly ignoring the dog did (Teixeira & Hall, 2021). So say goodbye the way you normally would.

If he already struggles when you leave, the ASPCA suggests keeping both ends quiet: a pat on the head, a goodbye, and out the door. When you get back, say hello, then leave the fuss until he is calm.

About that 3-3-3 rule

You have probably met it by now. Three days to decompress, three weeks to learn the routine, three months to feel at home. It is on shelter handouts, posted by SPCAs, and passed around in every adoption group there is.

It comes from the rescue world, and no study has tested it.

The first two thirds hold up. They buy a frightened dog patience at the start. The trouble is the finish line.

Three months is where the Lincoln interviews and the Ohio behavior data both say things are still moving. An owner who reaches month four with a difficult dog, holding a rule that says he should be finished, can easily decide that something is wrong with the dog.

Keep the patience the rule buys you. Move the finish line.

The dog who got harder

That paw he would not let you touch is the same paw he handed over without a word in week one. What has usually changed is that he trusts you enough now to say no about it. If it is only ever that paw, let your vet look at it.

The first weeks were a guest. What you have now is a dog, and he will go on arriving for months yet. Most of what will make him easy to live with has not happened.

For the wider picture of how anxiety works in dogs, our main guide to dog anxiety is the place to start.

Common questions

How long does it take for a rescue dog to settle?

Most adopted dogs in the research took longer than three months to settle. In a University of Lincoln study of 27 adopters, fewer than a third said their dog had settled within three months, and the largest group said four to six months. In an Ohio State study of 99 adopted dogs, a small drop in separation-related behavior came between month three and month six.

Should I get a second dog to keep him company?

A second dog is unlikely to fix a rescue dog’s separation problems. Research on separation-related behavior has repeatedly found no protective effect from living with other dogs, including in a UK cohort of more than a thousand (Harvey et al., 2022). The attachment driving the problem is to you, and another dog in the room does not stand in for it. It is a large decision to make on a thin hope.

Do I need to find out what happened to him before?

Wanting to know a rescue dog’s past is natural, and for most of them it is not available. In a large Finnish survey, the two environmental factors most strongly tied to fearfulness were how much socialization a dog had in his first three months and the quality of care his mother gave him (Tiira & Lohi, 2015). Neither is something you can find out for most rescue dogs, and neither is something you could undo if you did. What is in your hands is predictability, exercise and time.

He was perfect and now he’s difficult. Did I do something wrong?

When a rescue dog gets harder after an easy first few weeks, it is rarely because you did something wrong. More often it is because he no longer expects an objection to cost him anything. The pattern is common enough that people named it long before anyone studied it, and when researchers went looking they did find behavior moving in both directions over the first six months. If the new objection is to being touched in one particular spot, have your vet check it, because that can be pain.

When should I call a trainer or a behaviorist?

Call a trainer or behaviorist sooner than most people do, and do not wait if six to eight weeks of consistent work have not changed anything. If your dog panics every time you leave, keeps getting worse, hurts himself trying to get out, will not eat all day, starts growling at people, or snaps or bites, start with your vet. Look for someone who works reward-based only. AVSAB, the American Veterinary Society of Animal Behavior, recommends that only reward-based methods be used for all dog training, including the treatment of behavior problems, and the evidence on aversive methods runs the other way.

Sources

• van der Laan JE, Vinke CM, Arndt SS (2022). Evaluation of hair cortisol as an indicator of long-term stress responses in dogs in an animal shelter and after subsequent adoption. Scientific Reports.
• Bohland KR, Lilly ML, Herron ME, Arruda AG, O’Quin JM (2023). Shelter dog behavior after adoption: Using the C-BARQ to track dog behavior changes through the first six months after adoption. PLoS ONE 18(8): e0289356.
• Moyer BJ, Zulch H, Ventura BA, Burman O (2025). A qualitative exploration of owner experiences following dog adoption. Animal Welfare.
• Salonen M et al. (2020). Prevalence, comorbidity, and breed differences in canine anxiety in 13,700 Finnish pet dogs. Scientific Reports.
• Tiira K, Lohi H (2015). Early life experiences and exercise associate with canine anxieties. PLoS ONE.
• Teixeira AR, Hall NJ (2021). Effect of greeting and departure interactions on the development of increased separation-related behaviors in newly adopted adult dogs. Journal of Veterinary Behavior 41:22-32.
• Horwitz DF (2008). Separation Anxiety in Dogs. Clinician’s Brief, peer reviewed.
• Harvey ND, Christley RM, Giragosian K, Mead R, Murray JK, Samet L, Upjohn MM, Casey RA (2022). Impact of Changes in Time Left Alone on Separation-Related Behaviour in UK Pet Dogs. Animals 12(4):482.
• AVSAB (2021). Position Statement on Humane Dog Training.
• ASPCA. Separation Anxiety.