Should I Adopt a Second Pet?
According to Stephanie Borns-Weil, DVM, head of the Tufts Animal Behavior Clinic, "Because dogs are highly social creatures, getting another dog is the right thing to do ... I believe that dogs in general are happier with other dogs." Sharing a life with another dog or pet can often provide mental and physical stimulation and companionship that aids your pets' quality of life.
That said, for various reasons, some dogs don't do well living in homes with other pets. Before deciding to adopt a second pet, it's important that you take the time to introduce potential new family members to your dog and allow them to get acquainted. Otherwise, you could contribute to your canine's stress.

If your dog tends to get along with other dogs, but having a second pet isn't feasible for you, consider creating opportunities for them to meet other dogs and people at dog parks or doggy day care. These social experiences can do wonders for some dogs.
What If My Dog Isn't Acting Like a Friend?
Negative changes in a dog's behavior are often clues that something isn't working for your pet. Sudden antisocial tendencies could indicate that your dog is feeling ill or in pain. In some cases, this behavior can be a sign of jealousy or anxiety. And just as with humans, dogs' behaviors can change with age.
If you notice that your once-friendly dog is less cuddly or playful than before, a good first step is to head to your local veterinarian for a check-up. Pay attention to your pet to see if there are any other signs of ailment, such as limping, reduced appetite or loose stool. These signs are helpful for your vet in diagnosing health issues. And if everything checks out, it might be time to meet with a behaviorist who can help you understand your dog's behavior.
Also, consider any changes that you've made to your household. Did you move recently? Your dog might still feel anxious from living in a new home. What about a new roommate or new baby in the house? Changes like this can cause your dog to feel like their no longer the center of attention and become withdrawn or display undesirable behaviors. Have you been gone away on an extended vacation? There are a number of reasons why your dog might not be acting like your BFF beyond just health concerns. If your veterinarian gives your dog a clean bill of health, consider any major changes that have been made. In these situations, getting back to "normal" or reassuring them that you're still there for them might be what they need to get back to being their normal, friendly self.
So, do dogs have best friends? Yes, it's very possible that they do. And often, that best friend is you! Be sure to continually build your bond with your dog by taking walks, playing and otherwise establishing consistent routines that incorporate activities your pooch enjoys.