The tree went up on Saturday. By Sunday your 9 month old dog had removed 3 ornaments and carried tinsel to the kitchen. Then they unwrapped a present that turned out to be fudge.
None of that is spite. Your dog sees a room full of new objects that dangle, smell and roll. The house is busier and the routine looser. December is a management problem first.
It is also a safety problem. Several things that arrive with the decorations are dangerous if swallowed, and an adolescent dog still tests most new objects with their mouth.
What is actually in the room
The tree. A real tree drops needles, which can irritate your dog's mouth and stomach. The water in the stand can hold fertiliser, preservative additives and bacteria, so cover it. An artificial tree drops less, but loose plastic needles and fake snow are no better to eat.
Tinsel, ribbon and string. Anything long and thin is a particular risk if swallowed, because it can cause a serious blockage in the gut. Many households with an adolescent dog skip tinsel for a year or two.
Ornaments. Glass breaks into sharp pieces, and salt-dough ornaments carry a salt risk. Hang anything breakable, edible or homemade above the height your dog can reach standing up.
Chocolate. It turns up in advent calendars, in tins on the coffee table and in stockings. Chocolate is toxic to dogs, and darker chocolate is more dangerous.
Wrapped food gifts. Your dog can smell chocolate, nuts and dried fruit through paper. Raisins in fruitcake and holiday baking are toxic to dogs, and so is xylitol in some sugar-free sweets and gum.
Candles and lights. A wagging tail or a curious nose can reach a low candle. Keep flames high, and never leave one burning with your dog alone. Tuck light cables out of reach, because adolescent dogs chew.
Plants. Holly, mistletoe and poinsettia can make a dog unwell. Put them up high, or leave them out this year.
Pick one setup before the tree goes up
Decide how the tree and your dog will share the house before it comes in, rather than improvising after the first ornament goes missing. Any of these works. Switching between them halfway through the month is what goes wrong.
Put the tree in a room your dog does not use, and keep that door closed.
Put the tree behind a pen or baby gate panels, with a clear gap of 2 feet all the way round.
Keep the tree in the living room, leave the bottom third undecorated, and supervise every minute your dog is in there.
Dog-proof the rest of December
Make one room the dog-proof zone, with no tree, no food gifts and no candles, and a bed and a chew waiting.
Keep presents off the floor until the day they are opened. Anything containing food stays in a cupboard until then.
Hang advent calendars above counter height, and count the doors each morning so you know whether one has gone.
Ask visitors to keep bags and coats off the floor and away from your dog, because that is where the chocolate and gum live.
Hand over a chew before you start wrapping, decorating or cooking, so your dog has something to do while the house is busy.
Behaviour change is built from management plus reinforcement together. December calls for the management half most of the time, and the training can wait for a quieter week.
Leaving your dog alone with the tree
Do not. When you go out, your dog goes into the dog-proof room, or the tree room door closes behind you. The same goes for overnight. The tree is the most interesting object in the house, and nobody is there to trade for an ornament at 2pm.
If your dog grabs something
Trade rather than chase. Hold a handful of food at your dog's nose, say swap once, and feed piece by piece as they let go. Chasing turns stealing into a game, and an adolescent dog is faster than you.
Do not scold after the fact. Punishment-based approaches are associated with fear, avoidance and defensive aggression. A dog who expects trouble when you approach is more likely to run off with what they have.
If you want to practice, sit in the tree room and reward your dog for lying on a mat, 2 minutes at a time. Relaxation is trained as a behaviour in its own right, in short repeatable sets.
Safety note
If you think your dog has eaten tinsel, ribbon, string, chocolate, pine needles or an ornament, call your veterinarian or an emergency vet line now. Do this even if your dog seems fine, and do not make them vomit unless a veterinarian tells you to. If you can see string or tinsel hanging from your dog's mouth or rear end, do not pull it. Bring the wrapper or packaging with you, so the veterinarian knows what was eaten and how much.
This month's version, in one line: one setup for the tree, presents and calendars off the floor, and your dog never alone with the decorations.