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?

Almost always, 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 setting it down took him months.

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 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 shadowing, the following-you-from-room-to-room habit.

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, and those dogs had been home a median of ten months (Moyer et al., 2025).

Twenty-seven interviews is a small study, and it records what owners felt rather than what anyone measured. One detail makes it worth listening to anyway: when a participant gave a range, the researchers filed that dog under the shortest end of it. If those numbers are wrong, they are wrong in the generous direction.

The behavior data agrees about the timing. In the Ohio study, separation-related behavior and attachment both fell furthest between month three and month six.

Be straight about the size, though. The drop was small, and what the authors describe is a high proportion of adopted dogs showing separation-related behavior with some of them improving. Some rather than most.

What the timing buys you is worth having anyway. If you are at week six and nothing has moved, you have not missed a window.

When it isn’t just settling in

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

Timing. Separation distress arrives fast, usually 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. Settling in gets better week over week. Separation anxiety holds steady or worsens with repetition, because every panicked afternoon teaches 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 is worth taking to a professional in the week it starts, rather than waiting to see whether he grows out of it.

For scale: in a survey of more than 13,700 dogs, the severe form of separation anxiety turned up in around 5% (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, and they carry most of the weight.

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, and two weeks of that does more than anything else on this list.

The evidence here is professional consensus rather than a trial, and the consensus is close to unanimous (AVSAB, the American Veterinary Society of Animal Behavior, which writes the training guidance the profession works from). What it looks like hour by hour is in our calming routine guide.

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

Daily exercise is the environmental factor most strongly tied to separation anxiety in the research (Tiira & Lohi, 2015). The studies measure how much he gets rather than when he gets it, so the timing is practical rather than proven: a dog who has already been out has somewhere for the morning to go.

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. Come back while he is still relaxed, never after he has started up, because arriving home to a distressed dog teaches him that distress is what brings you back.

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 AVSAB names as the standard approach, and flooding, which the same document rules out.

4. Let people ignore him.

The instinct is to introduce him to everybody so he learns that people are fine. Reactions to strangers are among the things that climb 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. 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.

The old advice was to ignore the dog on the way out and again on the way in. Dogs who got a proper hello and goodbye were no more likely to develop separation problems than dogs who did not, and that was measured in newly adopted adult dogs specifically (Teixeira & Hall, 2021). Keep it calm and skip the cold shoulder.

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.

As far as anyone can trace it, it began as one rescuer’s rule of thumb, written down about fifteen years ago to give discouraged adopters something to hold on to. No study has tested it.

The first two thirds do honest work. They buy a frightened dog patience through the days when a family is most likely to decide this was a mistake. The trouble is the finish line.

Three months is precisely 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, tends to conclude that the problem is him.

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 changed is that he trusts you enough now to say no about 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?

Longer than three months for most of them. In the Lincoln interviews, fewer than a third of owners said their dog had settled inside three months, and the largest group said four to six. The behavior data agrees: the improvements in separation-related behavior and clinginess showed up mostly between month three and month six. Individual dogs vary enormously, and a dog with a longer or rougher history tends to sit at the slow end.

Should I get a second dog to keep him company?

Not for this reason. 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?

It is natural to want to, and it usually is not available. The two environmental factors most strongly tied to fearfulness in dogs are how much variety they met between three and fourteen weeks old and the quality of care their mother gave them (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, and those are also the things with the most evidence behind them.

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

Almost certainly the opposite. A dog who starts objecting to things is a dog who no longer expects the objection to cost him anything. The pattern is common enough that adopters 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.

When should I call a trainer or a behaviorist?

Sooner than most people do, and without hesitating if the trouble is aggression, if he injures himself when left alone, or if nothing has moved in six to eight weeks of consistent work. Look for someone who works reward-based only. The position of the AVSAB is that reward-based methods should 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.