Why Is My Pet Acting Differently? Understanding Sudden Behaviour Changes

Noticed your sweet pup suddenly growling at the postie, or your normally chatty cat hiding under the bed? Sudden changes in your pet’s behaviour can be surprising — and a little worrying, too. But don’t panic. From Petdirect’s expert pet-loving team, here’s a look at the most common causes of behavioural shifts in pets, and what you can do to help. Because when it comes to understanding pets, We Get Pet.

Common Causes Of Behavioural Changes

There are many reasons your pet might start acting out of character. Here are some of the most common:

• Health Issues: Pain or illness is a leading cause of behavioural changes. Subtle signs like changes in appetite, hiding, or irritability could point to underlying physical discomfort.
• Age-Related Changes: As pets age, they may become more anxious, sensitive or less playful. Cognitive decline can also lead to confusion or disorientation.
• Environmental Stress: New home? New baby? Construction next door? Routine shake-ups, loud noises, or a change in household dynamics can cause stress.
• Lack of Mental or Physical Stimulation: Bored pets may resort to destructive or attention-seeking behaviour.
• Diet or Digestive Issues: An upset tummy or poor nutrition can affect mood, energy levels and even aggression.

Always keep in mind that your pet isn’t misbehaving ‘just because’. Behaviour is often a way of communicating something deeper.

When To See A Vet

If your pet’s behaviour changes suddenly — especially if it’s dramatic, persistent, or includes signs like aggression, lethargy, or increased hiding — it’s always safest to start with a vet check. Medical issues can easily disguise themselves as behavioural problems. Your vet can rule out or treat things like:

• Arthritis or joint problems (especially in older pets)
• Dental pain or infections
• Digestive upset or food intolerances
• Fleas, worms or skin irritations

Supporting your pet’s wellbeing with regular worm and flea treatments and ongoing health supplements is a great way to stay proactive with their care.

Behavioural Triggers To Watch For

If your vet gives the all-clear, it’s time to play pet detective. Try to identify what might be triggering your pet’s new behaviour. Consider:

• Have there been changes to your pet’s routine, feeding or environment?
• Is there a new pet, baby or visitor in the household?
• Are they getting enough mental and physical stimulation?
• Have you changed pet food or treats recently?

For curious kitties or playful pups, under-stimulation can lead to sudden episodes of hyperactivity or destructive play. Tools like smart pet toys or feeders are great boredom busters. And if your pet’s more of an anxious type, browse our range of calming essentials, including pheromone diffusers and soothing supplements.

Steps To Support Calmer, Happier Behaviour

Once you’ve identified a likely cause, it’s time to take action. Depending on what’s triggering the change, you could try:

• Supplement Support: Try pet health supplements for skin, joints, digestion or calming benefits — all backed by smart pet science.
• Enriching Feeders and Play: Use smart feeders or interactive toys to keep their mind active and their tummy full.
• Diet Review: Pets can be sensitive to changes in food. Switch to premium nutrition like Hill’s Science Diet or Royal Canin, tailored to their life stage and health needs.
• Create Calm Spaces: Set up den-like beds or safe spots, especially if loud noises are the issue. Use aids like Adaptil or Feliway when needed.

If you’re unsure where to start, our pet-loving team is here to help. Chat with our customer care team or browse our top-rated picks from trusted pet parents around Aotearoa.

We Get That Pets Aren’t Always Predictable

Just like us, pets have a full range of emotions — and from time to time, those feelings show up in ways that seem puzzling. But with a little observation and a lot of love, you can often get to the heart of what’s going on and help them feel like themselves again.

If your furry, feathered or finned friend is acting differently, start with the basics: vet care, routine, nutrition and mental stimulation. Small changes can make a world of difference.

Need support? Explore our full pet care range online — and don’t forget to sign up for Pet Perks to earn rewards every time you shop. Because when you shop with Petdirect, you’re choosing expert care, reliable advice and pet-lovers that truly get it.