Mouthing, which is also referred to as "play biting," is a behavior that is totally normal in young puppies. Wee puppies nip their littermates to learn social skills through playtime, and they also use their mouths to navigate new, exciting objects in their surroundings. Mouthing sometimes continues into adulthood in canines who were never trained in bite inhibition or use of chew toys.
Play Biting Vs. Aggressive Biting
Aggressive behavior is not as widespread in puppies as it is in adult dogs, but it certainly can happen. Because of that, it's crucial to always be able to differentiate play biting from aggressive biting, regardless of a dog's age. If you ever think that your pooch is behaving in a fierce or aggressive manner with you or anyone else, human or animal, seek outside help for him, immediately. Dealing with aggressive dogs is extremely hazardous and requires the knowledge and expertise of a professional pet behaviorist, period. Speak to your veterinarian for recommendations of individuals in that field, and waste no time. Crucially, always isolate aggressive dogs far away from children and other pets.
If your doggie's posture is loose, then mouthing, rather than aggressive biting, is a strong likelihood. Dogs in fierce mode tend to take on rigid, strained and tense physiques and facial expressions -- not a fun look. Playful pooches, on the other hand, seem devoid of anxiety from head to toe. Although laid-back dogs often have crinkly muzzles, their expressions don't seem "tight."
Difference in Pain
Play biting usually doesn't hurt much. If a bite feels sharp and intensely painful, then the dog giving it to you probably feels aggressive. If a bite is strong enough to cause a wound, it's not frolicsome. Fierce bites also usually are much more rapid and abrupt than playful ones. For the well-being of everyone in your home, including your canine, never shrug off any hints of aggression.
Body language and vocalization can often help you determine whether a dog is playfully or aggressively biting. If a dog is growling and showing you his teeth, that's not a good sign. Observing tails often can be helpful for these purposes. If a pooch's tail is elevated and thrashing around in a rigid manner, then he might be in aggression mode. If it's near the ground and waving lightly, however, he might have peaceful and spirited intentions, instead.