So, you buy a puppy: ball of fluff, cute as a pin. You know at some point the growth has to stop, but when? And will your puppy ever mature into a calm, reserved dog? This is a bit like asking “how long is a piece of string?” and the answer is “it depends”. And let’s not confuse growing with maturity.
Kelly Roper (Dog breeder and exhibitor) writes in “dogs.lovetoknow.com”: Most canines reach their full size by the time they are 12 to 18 months old although it does take longer for some of the largest breeds to finish growing. Some breeds even reach a full frame within the first six months of life although it takes longer for the rest of the body to catch up. While there isn’t a single age at which all dogs reach full size, there are some general guidelines that vary based on breed size.
Small breeds, such as Boston Terriers, Jack Russell Terriers, Chihuahuas and Pugs, tend to reach their full-sized framework between six and eight months old and they’ll typically fill out to their full weight by 12 months old.
Medium breeds, such as Airedale Terrier, American Pit Bull Terrier, Border Collie and the Standard Poodle, reach their full-sized framework between 12 and 15 months old, but they usually won’t reach their full weight until they’re closer to 18 months old.
Large breeds, such as German Shepherds, Labrador Retrievers and Weimaraners, won’t reach their full-sized frame until 15 to 18 months old and their full adult weight until they’re about two years old.
Giant breeds, such as Mastiffs, Great Pyrenees, Saint Bernards and Newfoundlands, take the longest to reach full size. Their basic framework is in place by about 18 months old, but it can take until age two or three for them to reach full weight and muscle mass.
So, the size of your dog will depend on breed and gender, with female dogs normally smaller than their male counterparts. To give you an estimate of the size of your dog, you could try using an on-line puppy size calculator (www.puppychart.com). Another way to determine their size is based on the age as a puppy. In general, most dogs are at 60% of their adult height by the time they are four months old.
From a maturity perspective it is important to realize that breeds mature at different rates. Many people believe that they’ll only have to put up with a rambunctious puppy behavior for a year. While some dogs do reach maturity near the end of their first year of life, others take significantly longer to mature. For example, Border Collies and other herding dogs don’t begin behaving like grown-ups until they are approximately two years old, whereas Toy Poodles and Shih Tzus typically behave like mature adults by the time they are 12 to 15 months old. Our own experience is that our dog Finn (a Labradoodle) took almost 5 years to mature, or so it seemed to us!
If you’re bringing home a dog breed that takes a bit longer to mature than most, it’s important that you are mentally prepared to live with an adult size dog who continues to behave like a puppy for an extended time.
While most dogs remain playful throughout their lives, there is a big difference between the lively activity of a mature canine and the boundless exuberance and dicey judgment exhibited by most puppies.
What are the signs that a dog is maturing?
When you notice that your dog starts to exercise a little more restraint, it’s a safe bet that he or she is starting to mature.
So whatever age your dog is at or whatever level of maturity, love them for what they are, relax and enjoy the ride!