A DOG trainer has revealed the reason why your puppy is so naughty - and how to make it behave.
Jamie Huggett, who runs the Southern Cross K9 puppy school in Australia, also said there is a crunch period when your puppy is most likely to cause havoc.
Taking to Instagram, he said: "So is your dog between four and eight months of age and has suddenly stopped listening to you?
"They are likely to be going through what's called the flight instinct period.
"This is a critical development in all puppies and thankfully only lasts a couple of weeks.
"However, you need to be really, really careful during this period so that your dog doesn't form some really bad habits that are going to last a lifetime."
Jamie explained that the flight instinct period is a hangover from before dogs were domesticated.
He said: "So in nature it is where they would start to leave the mum and then start to explore their surroundings.
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"Now before four months of age your puppy would have seen you as a bit of a security blanket.
"They're not going to stray too far because they're not quite confident in their surroundings yet.
"Your puppy then gets a little bit older and starts to explore and then suddenly they stop listening to you and their obedience goes to absolute s**t."
Jamie said that dog owners should keep their pooches on a 10-15 metre long line during this period, to give them freedom without letting them run away.
He added that rewarding good behaviour with treats is a better way to encourage it than shouting at your puppy for being naughty.
Jamie said: "Where we can get ourselves in a lot of trouble here is we, during this period, allow our dogs opportunities to, say, blow off a recall or not listen to you when we really need it.
"So in short, during this period, only lasts a couple of weeks, make sure your dog's on a long line to prevent any mistakes.
"You don't want your dog running off to stuff, you don't want your dog blowing off your recall. Keep them on a long line.
"Use lots of rewards, keep it fun, make sure your dog enjoys the obedience and you'll be fine."
Exasperated puppy owners hailed Jamie's game-changing advice.
Jess said: "So true! My ten-month-old puppy has become terrified of things which never used to bother him, like nail clippers."
James said: "My pit bull is going through this phase right now."
Patrick said: "This is why I always carry my puppies in my backpack or fanny pack."
It comes after a woman who splashed out on a £2,000 morkie puppy was devastated when she turned out very differently.
Influencer Amber Nunyo revealed her bizarre experience after she picked up her pedigree pooch.
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She shared pics of the mutt's face and paws suddenly turning white, before it turned out that Jellybean was actually white all over.
Whatever Jellybean's natural colour, she remains a very good girl.