10 Rescue Dog Behaviors That First-Time Owners Mistake for “Problems”

Rescue dogs often get unfairly labelled as “problem dogs.” That they all come with fear, aggression, or other bad habits. But the reality is far more nuanced. While some rescues do struggle with behaviors shaped by neglect, trauma, or constant upheaval, others settle in with ease. The real question isn’t so much whether rescue dogs have behavior problems, but why those problems appear, and how we can help them overcome the past.

10 Common Behaviors You Might See in Your New Rescue Dog

While every rescue dog is unique, certain behavior patterns show up more often in dogs who’ve been through stress, neglect, or multiple homes. Here are some of the most common issues new adopters may encounter.

1.    Fear and Anxiety

Fear and anxiety are common challenges. For some rescue dogs, the roots lie in missed socialization during the critical 3–14 week period, leaving them unsure of how to cope with new people, places, or experiences. Others may carry the impact of traumatic pasts (abuse, neglect, or abandonment) that leave them wary of humans and fearful of everyday situations.

Fearfulness can even begin before birth. Puppies born to stressed mothers may grow up more anxious, fearful, or reactive because stress hormones affect their development and early care. This makes them more sensitive and less resilient when faced with change.

For many rescue dogs, even routine events such as vet visits, grooming appointments, or entering a new home can feel overwhelming when they don’t yet know if they are safe. These fears can surface as trembling, cowering, avoidance, or defensive behaviors, all signs that the dog is struggling to feel secure.

• RELATED: Top Stress Signals in Dogs Every Owner Should Know

Tips for Addressing Fear and Anxiety

• Provide stability: Create a safe environment where your dog feels secure.
• Set boundaries and routines: Consistency in meals, walks, and bathroom breaks builds trust and confidence.
• Use positive reinforcement: Reward desired behaviors with treats, praise, or play; interrupt and redirect rather than punish.
• Manage triggers: Identify situations that cause fear or anxiety and introduce them gradually at the dog’s pace.
• Respect the dog’s timeline: Progress varies—try not to rush your dog, and celebrate small steps.
• Offer mental and physical outlets: Puzzle toys, training, and daily exercise prevent stress and boredom.
• Consider calming aids: Under veterinary guidance, pheromone diffusers, anxiety wraps, or supplements may help reduce anxiety.

2.    Aggressive Behavior

Sometimes rescue dogs display aggressive behaviors such as growling, snapping, or in rare cases, biting. In most situations, this aggression is rooted in fear or poor socialization rather than a desire to harm.

Again, dogs that missed out on early exposure to different people, environments, and experiences during the critical 3–14 week puppy stage are more likely to feel threatened by strangers later in life. Other contributing factors include genetics and breed tendencies, isolation or confinement, past abuse, or simply a lack of positive experiences.

Common Triggers for Fear-Based Aggression in Rescue Dogs:

• Strangers reaching toward their head or approaching too closely, especially suddenly
• Being approached, petted, or hugged when lying down or sleeping
• Stressful or unfamiliar environments (e.g., vet clinics, grooming salons)
• Harsh training methods or past punishment
• Owner tension, anxiety, or inconsistent handling
• Other dogs or people making direct eye contact
• Inexperience being around children
• Restraint or being cornered, which blocks their escape route
• Discomfort with being handled or having a collar, harness, or leash put on
• Having their nails trimmed, ears plucked or cleaned, or being bathed or shaved
• Being touched in sensitive areas like tail, paws, or belly
• Loud noises like fireworks or thunder
• Past traumatic experiences or punishment, especially if associated with certain objects or situations

Remember, aggressive behavior is usually a defense mechanism, not an inherent trait.

• RELATED: 15 Things That Terrify Dogs (And How You Can Help Them Feel Safe)

3. Incomplete House Training

Many rescue dogs come into new homes without ever having been properly house trained. Some may have lived outdoors, in kennels, or in environments where they could relieve themselves whenever they needed. Others may have learned inconsistent habits if their previous owners didn’t provide clear guidance.

Signs of incomplete house training include frequent accidents indoors, confusion about where to go, or reluctance to eliminate outside. This isn’t your dog trying to be difficult. It simply means she hasn’t yet learned the rules of living in a home.

Simple House-Training Plan for Rescue Dogs

• Set a schedule: Take your dog out first thing in the morning, after meals, naps, and play sessions.
• Supervise closely: Keep her within sight indoors to prevent accidents.
• Watch for signals: Sniffing the ground, pacing, circling, or pawing at the floor often mean a dog needs to go.
• Use confinement wisely: When you can’t supervise, a crate or small dog-proofed area can help (but make sure being confined doesn’t cause your dog any distress).
• Reward immediately: Praise and give a treat the second your dog eliminates outside.
• Interrupt gently: If you catch your dog mid-accident, calmly redirect her outdoors and never punish.
• Stay consistent: Repeat the routine daily so your dog learns what’s expected.

4. Lack of Basic Manners

Rescue dogs often arrive without the foundation of basic training. Simple behaviors many owners expect, like not jumping up on people, coming when called, or waiting calmly at doors, may never have been taught. In shelters or neglectful homes, dogs usually don’t receive consistent guidance, so they simply don’t know what’s expected in a family setting. These issues aren’t signs of a “bad dog,” but rather gaps in training.

Tips for Teaching Good Manners:

• Start with one behavior at a time (e.g., “sit” before meals).
• Reward desired behavior immediately with treats or praise.
• Ignore or redirect unwanted behavior (e.g., turn away when the dog jumps).
• Keep training sessions short and positive to maintain focus.
• Practice consistently in different settings so the behavior sticks.

5. Separation Anxiety

Some dogs are more vulnerable to separation anxiety because of their history, while others develop it in response to changes in their environment. As highly social animals, dogs form strong attachments to their caregivers and can feel distressed when left alone. This distress is often intensified by experiences such as abandonment, rehoming, or sudden changes in routine, home, or family structure. Even being left alone for the first time after constant companionship can trigger anxiety.

Recognizing and Managing Separation Anxiety

• Identifying triggers and behaviors: Many dogs become anxious at “departure cues” such as picking up keys or putting on shoes. Mixing up your routine—like picking up your keys and putting them in your pocket well before you leave—can reduce this anticipation.
• Positive reinforcement training: Start small by leaving the room for just a few seconds (or however long your dog can cope with) and rewarding calm behavior, gradually building duration over time (without trying to rush).
• Desensitization and counterconditioning: Slowly increase the time your dog spends alone while pairing departures with positive experiences, like a favorite toy or treat.
• Environmental enrichment: Provide a cozy, familiar space with comfortable bedding, your scent on clothing, and interactive toys such as KONGs, LickiMats, or Snuffle Mats. Mental stimulation helps distract from stress.
• Exercise and routine: A walk or play session before you leave can help your dog feel more relaxed. A predictable routine also builds security, though it’s still important to desensitize them to being alone.
• Consider a pet sitter: For dogs struggling with longer absences, a trusted pet sitter can offer companionship and reduce stress.

Managing separation anxiety takes time, consistency, and often the support of a canine separation anxiety specialist. Experts like Malena DeMartini or Julie Naismith, along with their teams, offer personalized online training programs that can guide owners through the process step by step.

6. Escaping

Some rescue dogs quickly become escape artists, especially in the early days. This behavior is usually fueled by fear or confusion, and, most of all, not knowing if they are safe. Being unsure about one’s personal safety is profoundly stressful (for humans too), and that insecurity can trigger a flight response. Bolting through doors, digging under fences, or jumping over barriers are instinctive attempts to get away from a place a dog doesn’t yet know if she can trust.

Managing Escape Risks:

• Keep your dog leashed during the early adjustment period.
• Supervise closely when outdoors and secure all exits.
• Use baby gates, double-leashing, a long line, and/or a secure harness for extra safety.
• Establish predictable routines to reduce stress and build trust.
• Allow time for your dog to bond and see his new home as a safe space.

Usually, dogs stop trying to escape once they realize they are safe in their new home. As they bond with their new family, they gradually build a “trust account” and gain confidence. They begin to associate their new home with nice things, like shelter from the elements, good food, a warm bed, fun toys, walks, and playtime.

Over time, these positive experiences reinforce a sense of safety, making their surroundings feel familiar and rewarding, and the urge to escape naturally fades away. For some dogs this happens quickly, within days or weeks, while others may take longer. Either way, for peace of mind, make sure your dog has a microchip and wears an ID tag—just in case.

7. Destructive Behavior

Digging up the garden, tearing up cushions, scratching at doors, or chewing furniture are all destructive behaviors commonly seen in rescue dogs. These actions are never about being “naughty” or “difficult,” but are coping strategies.

Why Destructive Behavior Happens:

• Separation anxiety: Dogs who’ve experienced abandonment or multiple transitions may chew or dig when left alone to ease their distress.
• Past trauma: Unstable or frightening environments can create stress responses, leading dogs to shred, chew, or break objects as a way to cope.
• Boredom and lack of exercise: Dogs without sufficient outlets for energy often entertain themselves through destructive chewing or digging.
• Additional triggers: Loud noises, sudden changes in routine, or unfamiliar environments can all heighten anxiety and spark destructive behavior.
• Health issues: Dental pain or malnutrition can make chewing especially appealing.

Strategies to Reduce Destructive Behavior:

• Provide daily physical exercise and mental enrichment through walks, play, interactive toys, and training sessions.
• Offer safe, durable chew toys and rotate them regularly, rewarding your dog for using them.
• Supervise and redirect early on—calmly guide your dog to appropriate outlets and reward good choices.
• Dog-proof your home by keeping tempting items out of reach and using gates or barriers when unsupervised.
• For diggers, create a designated digging spot and praise them for using it.
• Maintain a consistent routine to provide stability and reduce stress.
• Never punish destructive behavior, as this can increase fear and anxiety. Interrupt and  redirect instead.

8. Hyperactivity

Some rescue dogs seem endlessly “on the go,” bouncing, barking, or unable to settle. Hyperactivity is often linked to underlying stressors rather than simple “excitability.”

Common Causes of Hyperactivity:

• Sensory overload: Adjusting to unfamiliar sights, sounds, and smells in a new environment can leave dogs feeling restless.
• Anxiety and hyper-vigilance: Dogs with a history of neglect or instability may struggle to relax and stay constantly “on alert.”
• Breed and energy level: High-energy breeds and naturally excitable individuals are also more prone to hyperactivity, especially if they haven’t yet learned impulse control or self-calming skills.
• Boredom and lack of stimulation: Without sufficient activity, excess energy often spills into jumping, chewing, or barking.
• Inconsistent routines: Mixed signals and unclear boundaries can lead to unpredictable, restless behavior.

Puppies and young dogs are naturally more energetic and may only appear hyperactive until they mature and receive training. Less commonly, medical issues like hyperthyroidism or allergies may play a role. Medical issues aside, hyperactivity usually fades as rescue dogs adjust and learn to channel their energy productively as they settle into their new home.

9. Pulling on the Leash

For many rescue dogs, the leash is a brand-new concept, and they haven’t yet learned how to walk politely alongside a person. Add in their natural tendency to walk faster than humans and their strong drive to explore through sniffing, and pulling quickly becomes the default.

Why Dogs Pull on the Leash:

• Lack of prior training: Without experience on a leash, dogs don’t know they’re expected to walk at their handler’s pace.
• Natural instincts and exploration: Sniffing and investigating is highly rewarding, and pulling gets them there faster.
• Mismatched pace: Dogs move more quickly than humans, so they naturally surge ahead unless taught otherwise.
• Learned behavior: If pulling makes the walk continue, dogs quickly learn it “works.”
• Excess energy or overstimulation: Dogs with pent-up energy or who are new to busy environments are more likely to pull.

Quick Training Tips:

• Stop walking when the dog pulls, and move forward only when the leash is loose.
• Reward calm walking at your side with high value treats (or praise, if your dog enjoys that).
• Allow planned “sniff breaks” so your dog’s needs are met without constant pulling.
• Use a well-fitted harness (ideally with front and back clips) instead of a flat collar, not only for safety but also for greater comfort and control.

10. Excessive Barking

Excessive barking is often rooted in fear or anxiety, but can also stem from boredom, frustration, or unmet needs. Some dogs also bark when left alone due to separation anxiety, while others bark at every little unfamiliar sound.

In some cases, barking becomes a learned behavior if it reliably gains attention or access to something the dog wants. Ultimately, barking is a way for dogs to express stress, insecurity, or excess energy, and understanding the cause is the first step toward reducing it.

Strategies to Reduce Excessive Barking:

• Provide daily exercise and enrichment with walks, puzzle toys, and scent games.
• Establish consistent routines to create stability and reduce reactivity.
• Reinforce calm behavior with positive rewards, and avoid punishment, which can escalate anxiety.
• Redirect barking with engaging activities or training exercises that teach alternative responses.
• For persistent issues, especially separation anxiety, seek help from a qualified behavior professional or veterinarian.

What the Science Says About Rescue Dogs

A study conducted in New Zealand found that:

• A significant majority (70%) of adopted adolescent and adult dogs exhibited at least one problem behavior post-adoption.
• The most frequently reported problem behaviors were poor manners (46%), destruction of household items (30%), and excessively high energy (28%).
• While aggressive behaviors were less common, they still occurred in about 19% of cases.
• Despite the prevalence of problem behaviors, the majority of adopters (87%) expressed little to no concern regarding these issues.

Similarly, an Australian study revealed that:

• Undesirable behaviors were present in 53.3% of adopted dogs post-adoption.
• Interestingly, dogs with reported behavior problems had spent less time in the shelter compared to those without reported problems, suggesting that a shorter shelter stay might be linked to the manifestation of these issues.

A second Australian study reported that:

• Common issues during the initial post-adoptive period included hyperactivity, compatibility issues with existing pets, and pulling on the leash.
• Escaping was strongly associated with separation-related problems.

While a US-based study found the following:

• One week after adoption, house training was the most commonly reported behavior problem.

Despite the prevalence of behavioral issues, research shows that:

• Adopters expressed high levels of satisfaction with their new pets.
• In the first Australian study, satisfaction scores were very high for both cats and dogs, with means of 4.9 and 4.8 out of 5, respectively.

However, it’s important to note that behavior problems, particularly aggression toward humans, are among the top reasons owners return dogs to shelters. In the US, the return rate of companion animals to shelters within the first six months of adoption ranges from 7% to 20%, with behavior issues being a significant contributing factor.

Research also suggests that younger adopters (ages 25–34) and those who receive advice and support from loved ones or professionals showed higher rates of pet retention. Surprisingly, doing research on pet ownership prior to adoption and having previous pet ownership experience does not significantly impact retention rates.

When to Seek Professional Help for Rescue Dog Behavior

• Severe aggression: Biting, lunging, or hostility toward people or animals should be addressed immediately with a positive reinforcement-based training and behavior professional for safety and targeted treatment.
• Persistent anxiety or phobias: If fear or anxiety severely impacts your dog’s quality of life and doesn’t improve with at-home strategies, professional guidance can provide customized desensitization and counter-conditioning plans.
• Lack of training progress: When consistent effort isn’t producing results, a skilled trainer can refine your techniques, identify problem areas, and offer tailored guidance.

Seeking professional help is not a sign of failure, but rather a testament to your commitment to your rescue dog’s well-being. A qualified trainer or behavior professional can provide invaluable insights, support, and guidance, helping you navigate even the most challenging behavioral issues with confidence and compassion.

References

• Adopting Shelter Dogs: Owner Experiences of the First Month Post-Adoption – Linda C. Marston, Pauleen C Bennett, & Grahame Coleman
• Factors Informing the Return of Adopted Dogs and Cats to an Animal Shelter – Sloane M. Hawes, Josephine M. Kerrigan, Tess Hupe, & Kevin N. Morris
• Follow-up Surveys of People Who Have Adopted Dogs and Cats from An Australian Shelter – Sophie Scott, Evelien Jong, Michelle L Mcarthur, & Susan Hazel
• Health and Behavior Problems in Dogs and Cats One Week and One Month after Adoption From Animal Shelters – Linda K Lord, Linda Reider, Meghan E Herron, & Kristy Graszak
• Post-Adoption Problem Behaviours in Adolescent and Adult Dogs Rehomed through a New Zealand Animal Shelter – M. Carolyn Gates, Sarah Zito, Julia Thomas, & Arnja Dale

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