Whether it's puppies, kittens or children, Nature insists on play. Play is a requirement for healthy development of a loving personality as well as for a healthy body. In addition, play is the basis for a social structure. Individuals of any species that do not play when they are young are severely mentally and socially compromised when they become adults.

Socializing should begin no later than six weeks in puppies. Pets who learn to play early, and play a lot, tend to retain that playfulness later in life. This has several benefits to the pet:

• Cardiovascular development
• Balance and coordination
• Joint lubrication
• Hunting and fighting skills
• Easier and more fun for the owner to exercise the pet (e.g., throw a ball, or drag a string).
• More fun in life for the dog
• Owner usually enjoys watching (and participating), so pet is more entertaining. This increases the owner-animal bond.

Though a related species, dogs play more than wolves. In wolves, play decreases soon after puberty. In dogs, we have bred/selected over time for playfulness to continue throughout the animal's life. This is no accident. Humans have bred dogs for this "juvenile" behavior, because we value playfulness as a personality characteristic in pets. We should provide toys and encourage non-destructive play as much as possible, starting as early in life as possible.

In genetics, when a juvenile trait is selectively bred, the resulting species is said to be "neotenized." One animal behaviorist jokingly wondered aloud, "Are humans really neotenized chimpanzees?"

Aggressive Play
Play fighting between puppies usually does not result in an aggressive adult dog. It's a way for puppies to determine their rank in the litter and for adult dogs to cement theirs with the pack. However, rough play between people and dogs over 6 months often turns out badly. The aggressive threshold is lowered because the dog is rewarded by the fun of growling and tooth grabbing a human. Guard dog breeds have a genetically lower aggressive threshold, so they love the rough play, but are also more likely to escalate the aggression later, but usually toward a different human.

Aggressive play allows the dog to show aggressive symptoms toward humans, and enjoy doing it!  Aggressive play in puppies may also lead to aggression in adults.

Dog Play Body Language
Dogs use a variety of body language signals to display playfulness. An individual dog may show any combination of these play signals:

• Play Bow - Slapping both front legs on the ground with the rump up in the air.
• Exaggerated Looking Away - Focusing on you while pretending to look away
• Pawing With Front Paw - This is the solicitation gesture; roughly means "Please."
• Prancing ZIG And Zag Leaps - Lots of energy and joy.
• Chase Behavior - Canine equivalent of starting a tag game
• Play Facial Expression - Distinct once you start looking for it
• Frequent Role Reversal - Pushy dogs acting submissive to signal non-threatening play

Actively encourage your dog to engage in appropriate play from an early age. Rotate two or three safe toys to play with each day. Praise any interest or chewing on toys.

Rules Of Fair Play When Playing With Your Dog
Here are four guidelines for appropriate dog play. These are basic rules; if your dog violates any of them, stop the play for at least 30 seconds i.e. give the dog a "time out" then require a SIT before resuming play. Train him or her to "play fair" by these rules:

1) No canine teeth grab skin or clothes. Never permit aggressive play with tooth contact.
2) Human decides on beginning and ending of play session (to retain leadership).
3) Human usually wins, but it is fun when the dog wins occasionally also.
4) If the dog wants to play more than the human, redirect his energy into a chew toy.

Safe Games To Play With Your Dog

Tag: I touch you, then you touch me. (No teeth!) Kids especially love this game.

Hide and Seek: Can you find where I hid your bone (toy)? Can you find me at the dog park after dark? Kids can play this game: Give a ¼ inch piece of hot dog. Tell the dog STAY. Run and hide, then yell come. When the dog finds you, say SIT, give another piece, then repeat STAY. If the dog does not stay, it is time for an obedience refresher course.

Fetch: Ball or flying disc. Praise anything close at first, then praise more specifically. Start with the dog right in front of you, and teach TAKE IT and DROP IT. If the dog will not drop the toy, have a second ball, and trade for the one the dog has.

Grooming: Pretend to prepare the dog for an appearance as the star of a TV commercial.

Wrestling: This is the same as restraint and handling. The goal is to get the dog to "Give" in several different positions. Make sure you win at the end of the game.

Tug of War: Follow basic rules above. Use an owner designated toy.

Explorer: Leash or harness the dog and discover wilderness (or your neighborhood) together.

In the final analysis, play is a great way to spend time with your pets, and when done correctly actually contributes to the mental health of all involved.