​Puppy Shark Phase: Teething, Biting, Adult Teeth, and What Owners Need to Watch
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Puppy Shark Phase is often just teething in action. Before owners assume a puppy is mean, aggressive, or developing behavior problems, they need to understand what is actually happening in the mouth. Puppies chew, nip, and mouth more during this stage because baby teeth are changing, adult teeth are coming in, and the mouth is often uncomfortable. That does not mean the puppy is bad. It means the puppy is growing, teething, and needs correct management, appropriate chew outlets, and owners who are paying attention.
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Most owners think of teething only when a puppy is chewing on furniture, crate bars, shoes, cords, or anything else within reach. What many do not think about is the other part of it: the puppy that will not stop chewing on hands, sleeves, ankles, pant legs, and anything else moving nearby.
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That is where people often get it wrong.
A young puppy in puppy shark phase is usually not being mean, aggressive, or behaviorally unsound. Puppies explore the world with their mouths. Nipping, mouthing, and play-biting are common puppy behaviors, and teething adds even more chewing drive and mouth sensitivity on top of that. Veterinary behavior guidance notes that puppy biting is commonly part of normal social play, while teething more often increases gnawing and chewing. That means a mouthy puppy is not automatically an aggressive puppy.
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Puppies first develop baby teeth, also called deciduous teeth. Those baby teeth begin erupting at about 3 to 5 weeks of age. Later, the baby teeth loosen and fall out as the permanent adult teeth come in. Permanent teeth generally begin erupting around 4 to 5 months of age, and most dogs should have their full adult dentition by about 6 to 7 months. Dogs have 28 baby teeth and 42 permanent adult teeth.
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That timeline matters because teething is not just a quick little stage. Mouth changes continue for months. Even after the major tooth changes are underway, some puppies still have a strong need to chew because chewing helps soothe gum discomfort and oral sensitivity. UC Davis notes that dental problems in dogs are common and that owners need to pay attention to the mouth early rather than treat it as an afterthought.
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So when a young puppy is biting at hands and ankles, owners need to think clearly before labeling that puppy as aggressive or bad. In many cases, the puppy is being exactly what it is: a normal puppy with a busy mouth. That does not mean the behavior should be ignored. It means it should be understood correctly and redirected correctly. Puppies in this stage need structure, supervision, and appropriate chew outlets. They need safe items they are allowed to chew. They need redirection away from human hands, clothes, and furniture. They do not need owners assuming every mouthy puppy has a serious behavioral problem.
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One of the biggest things owners should physically watch for during this dental transition is retained baby teeth, especially retained baby canines. This happens when the baby tooth does not fall out on time and the permanent tooth erupts next to it. When that happens, the dog may temporarily have two teeth in the same place. That is not something to ignore. VCA notes that retained deciduous teeth can cause malocclusion, discomfort, food trapping, and future dental disease. They specifically advise checking the mouth weekly until about 7 to 8 months of age to make sure the teeth are developing normally.
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Owners should check the mouth regularly while the adult teeth are coming in. If a permanent canine is erupting and the baby canine is still sitting there beside it, that needs veterinary attention. Waiting too long can allow the permanent tooth to settle into the wrong position and contribute to crowding, trapped debris, odor, and periodontal trouble later.
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This is why teething is not just about chewed-up furniture. It is also about dental development, oral comfort, and catching problems early. A puppy may be chewing because the mouth hurts. A puppy may be nipping because puppies naturally use their mouths during play and development. A puppy may be mouthy because it is teething, overstimulated, under-redirected, or simply acting its age. That is very different from calling the puppy aggressive.
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Dental care also does not stop once the puppy teeth are gone. Teeth should be checked during normal veterinary wellness visits. The veterinarian should evaluate tooth alignment, gum health, tartar buildup, retained baby teeth, fractured teeth, and whether professional dental cleaning is needed. UC Davis states that periodontal disease is the most common dental condition affecting dogs and cats, and that more than 80 percent of dogs develop gum disease by three years of age.
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At home, owners should get used to looking in the dog’s mouth. Lift the lips. Check the gumline. Watch for retained baby canines, crowding, redness, odor, tartar, or anything that does not look right. Early awareness prevents bigger problems later. A puppy in puppy shark phase is usually not trying to be bad. More often, that puppy is teething, growing, exploring, and trying to soothe a changing mouth. The job is not to panic. The job is to manage it correctly, redirect it appropriately, and pay attention while the teeth are changing