Halloween is a peculiar holiday, especially for dogs. We two-legged beings all look different, and what’s with the constant doorbell-ringing? Weren’t you just here. Oh, I’m sorry. You're Batman. He-Man was just here. My bad. I’ll keep barking. Dogs don’t exactly excel at Halloween, and here’s the lowdown on dogs, costumes, tricks, and treats.

1) Costumes

Some species were made to jump in to a Halloween costume parade. And while many people enjoy putting dogs in costumes, it's octopuses who top my list as Halloween showoffs because they can show up in any number of costumes depending on the environment around them.

Katherine Harmon Courage (Twitter), a contributing Sci Am editor and author of the recent release, Octopus!: The Most Mysterious Creature in the Sea, explains how octopuses go about changing their outer garb, “The first and most well known are the chromatophores, small sacs of different colored pigment that can expand or contract changing the animal’s overall hue and pattern. Augmenting that are irridophores, which can reflect light and also lend coloring to the display, and leucophores, white cells that provide a crisp background.”

Imagine if you are an octopus and every Halloween you show up wearing a different self-generated costume. You'd have Best Costume Contest in the bag!

Back on land, the superb lyrebird’s costume seems relatively unexceptional, but when they open their mouths, we find their costume is on the inside. Often described as the "greatest mimic in the world,” the superb lyrebird has a truly amazing voice that not only mimics other species, but it can also mimic man-made sounds like car alarms and camera shutters. Uhm, I can do a good impression of my mom. Does that count?

Dogs are a bit different from octopuses and lyrebirds. While some dogs let themselves be turned into a spider or Elvis (both are equally meaningless to dogs), some costumes are uncomfortable, particularly those that impede gait or restrict movement. Anything with booties comes to mind:

2) Dogs Can Be Tricked

We like to say that dogs have ‘such great noses’ because, compared to us, they do. The quantity and quality of their olfactory experience is much more grand than ours, but sometimes, even with their great sniffers, they can be tricked.

Take the dog below: you might assume this dog would figure out that the statue will never ever be able to throw that stick. So why is the dog not getting it? Well, the outward shape of the statue is entirely human-like as is the sitting position. There could even be traces of human smell on the statue where people have touched it or sat on it. Regardless, the statue doesn’t have all the elements of life. Nonetheless, this dog would greatly appreciate if you, kind statue, would throw the stick.

3) Isn’t Everything a Treat?

Dogs are not all that discerning when it comes to what they’ll eat. A plastic duck? Certainly. Pennies? Even though they can lead to zinc poisoning and death? Yes please.

When it comes to food aversion in dogs, they can be “slow to learn and quick to forget.” While cats exposed to a single meal with lithium chloride -- a substance commonly used to test food aversion learning -- refused that same food three days later, “dogs repeatedly ate the vomitus induced, and while they rejected the type of meat used to administer the lithium chloride for at least 7 hours, after 24 hours they would eat it once again.” This does not bode well for companion dog owners who want their dogs to stay alive and not self-sabotage on chocolate or pennies.

Ultimately, companion dogs ingest both comestibles and non-comestibles, and substances that can kill them. In preparation for Halloween (but really something that’s important all the time), the ASPCA reminds owners, “Chocolate in all forms—especially dark or baking chocolate—can be very dangerous for dogs and cats. Candies containing the artificial sweetener xylitol can also cause problems. If you do suspect your pet has ingested something toxic, please call your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435.”

So if you dressed your dog as a witch for Halloween and she came back with a mountain of fun-size Snickers bars, please don’t let her eat them. Instead, please send all Snickers bars to the Dog Spies office here at Scientific American.


Photo: Cheerleader dog costume for Halloween, Flickr Creative Commons


Ackerman et al. 1990. Zinc toxicosis in a dog secondary to ingestion of pennies. Veterinary Radiology 31, 155–157.

Bradshaw, J. W. S. 1991. Sensory and experiential factors in the design of foods for domestic dogs and cats. Proceedings of the Nutritional Society 50, 99–106.

Dalziell, A. & Magrath, R. D. 2013. Fooling the experts: accurate vocal mimicry in the song of the superb lyrebird, Menura novaehollandiae. Animal Behaviour 83, 1401–1410.

Stuart-Fox, D. & Moussalli, A. 2009. Camouflage, communication and thermoregulation: lessons from colour changing organisms. Philos Trans R Soc Lond B Biol Sci. 27, 463–70.