Is the Moon Driving My Cat Insane?

Like many pet owners, my partner and I have a long list of nonsensical nicknames for our 10-year-old tabby, Ace: sugarplum, booboo, Angela Merkel, sharp claw, clompers, night fury, poof ball. But we reserve one nickname for a very specific time each month, when Ace is more restless than usual in the daytime hours, skulking around from room to room instead of snoozing on a blanket. Or when his evening sprints become turbocharged, and he parkours off the walls and the furniture to achieve maximum speed. On those nights, the moon hangs bright in the dark sky, almost entirely illuminated. Then, we call him the waning gibbous.

I don’t remember when I first decided to draw a connection between Ace’s zoomies and the moon, but pet websites bolstered my belief, even if they read like feline horoscopes. Besides, cats are mystical creatures of the night, the supernatural companions of witches, and all-around spooky. Ace’s wildness didn’t always match up with a waning gibbous, but it happened enough for me to keep the joke going, and start to wonder whether there might be a slice of truth in it. Other animals on Earth eat, grow, and live in tune with the moon. What about my eight-pound sugarplum?

The moon has long been falsely blamed for all sorts of odd human behaviors. Researchers have firmly debunked claims that a full moon causes more crime or emergency-room visits as pseudoscience. But veterinarians, cat researchers, and feline-behavior experts told me that the relationship between felines and the moon has barely been studied. No concrete evidence has definitively linked changes in feline behavior to the phases of the lunar cycle, but the sheer absence of evidence is not evidence of absence. “I wouldn’t say the case is closed,” Mikel Delgado, a cat-behavior consultant in California and the author of Play With Your Cat!, told me.

Among people who work with animals, fears of the full moon persist. “It was very common, and it still is common, for people who work in veterinary hospitals to start feeling anxious around a full moon and make comments to each other—Don’t jinx me; we’re going to see some crazy stuff,” Raegan Wells, an emergency-room veterinarian in Arizona, told me. Back in the 2000s, Wells and her colleagues at Colorado State University analyzed the cases of nearly 12,000 dogs and cats treated at the school’s veterinary-medicine center; their study found that the risk of emergencies was highest on days when the moon was mostly illuminated—during the waxing-gibbous, full, and waning-gibbous phases. But the researchers couldn’t say whether those additional emergencies were caused by lunar zoomies or were merely a statistical artifact.

Cat experts have a couple of theories for how the lunar cycle could, potentially, affect feline behavior. The extra glow of a full moon could embolden cats to explore more, “taking risks and doing things they normally wouldn’t do,” Britt Florkiewicz, an evolutionary psychologist and professor at Lyon College in Arkansas who studies facial signaling in cats and other animals, told me. A new moon could encourage them in a different way; when the night is darker, cats’ vision gives them an advantage. A study of outdoor cats, published last year, found that the animals were most nocturnally active around the time of a new moon. But it’s unclear whether indoor cats like mine could exhibit a similar tendency from their vantage point on the windowsill. Carlo Siracusa, a veterinary behaviorist at the University of Pennsylvania’s School of Veterinary Medicine, told me that his cat, Elsa, often stares at the full moon from the top floor of his house, where the window provides a lovely view. Perhaps other cats do the same because the moonlight casts shadows on the walls of their home, Siracusa said. Cats are suckers for shadows.

Cats might be no more responsive to the specific waxing and waning of the moon than they are to any other changes in their environment, Siracusa said. In fact, he said, discovering something new in their vicinity is one of the two main triggers for cats to engage in zoomies. (The other is when they sense that they’re about to be fed.) During the pandemic, Siracusa saw an uptick in cats exhibiting aggression, a change he attributes to their owners suddenly working from home. “Spaces and times that were before pretty consistently predictable suddenly became very unpredictable,” Siracusa said. His patients’ owners propose all kinds of explanations for their cats’ behavior, and he always takes them seriously. “There are so many factors that can influence the behavior of a cat that just dismissing what someone says and saying, No, that’s just fantasy—I don’t think that’s appropriate,” he said.

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Humans have a natural tendency to draw associations and spot patterns, which makes pet owners masters of projection. When Wells and I spoke last week during a full moon, she reported that her cat Roy “has gotten into a lot more mischief this last 24 hours than is typical for him.” But she suspects that she noticed only because she had been thinking about our interview, and she had checked the moon phase. Plus, her family had just put up Halloween decorations, introducing novelty to the cat’s surroundings—perhaps that was why. Or maybe Roy, who is only a year old, is “just being a stinker,” Wells said.

Ace is the king of the household whether the moon is glowing or not. I like to watch him when he’s dozing in one of his favorite spots: on top of a small ottoman that we brought home last year from a yard sale so that we could finally put our feet up in front of the television, and that now serves as a literal pedestal for our fluffy boy. Moonsplaining, too, can create a sort of awestruck distance between cat owners and our pets; it casts them as mystifying creatures, not of this world, their true nature determined by celestial forces that mere mortals can only hope to comprehend. But it is fundamentally an attempt to better understand the inner lives of these small animals we share our lives with. “Humans are really bad at not anthropomorphizing and allowing our pets to be the species that they are,” Delgado said. Still, we are fantastically good at loving the animals that live with us, even in ways that defy logic. Maybe my cat is a little moon-crazy, or maybe I am. Either way, Ace will always be a waning gibbous to me.