The Donkey vs. Mule Quicksand Myth: Debunked

You've probably heard this one before: a donkey will sink in quicksand, but a mule won't. It's been repeated in trivia lists, forwarded in emails, and shared on social media for years. There's just one problem—it's not true.

This colorful claim is folklore dressed up as animal behavior, a parable about staying calm under pressure rather than a documented difference between these two equines. Let's dig into the science and see why this myth won't hold up.

The Physics: Why Nothing (Including Donkeys) Fully Sinks

Here's what actually happens in quicksand: it's a saturated mixture of sand and water that looks solid but liquefies under stress. When you step on it, it collapses beneath you. Sounds terrifying, right?

But here's the key fact from actual scientific research published in Nature: quicksand is about twice as dense as a human or animal body. That means you'll sink partway in—maybe up to your waist—but you won't be swallowed whole like in the movies. The same physics applies whether you're a donkey, a mule, a horse, or a human.

Dutch and French researchers demonstrated that objects with a density of 1 g/ml (like living creatures) simply cannot sink completely in quicksand. The mixture won't allow it. You'd float at about the halfway point, assuming you stop moving.

The Movement Problem

The real danger in quicksand isn't sinking—it's struggling. When you thrash around trying to escape, you cause the quicksand to liquefy further and create a suction effect around your limbs. Just a 1% change in stress can drop the viscosity of quicksand by nearly a million times, turning solid-seeming ground into a gooey trap.

This is where the donkey vs. mule story probably originated. The myth suggests that:

• Donkeys panic and struggle when caught, sealing their doom
• Mules stay calm and can work themselves free
• Therefore, mules are smarter or better suited to survival

But there's no scientific documentation of this behavioral difference in quicksand situations. While donkeys and mules do have different temperaments generally—mules are horse-donkey hybrids known for being cautious and measured—there's no evidence they respond differently to quicksand specifically.

Why the Myth Persists

This tale endures because it's a perfect metaphor. It teaches a valuable lesson: when you're in trouble, stay calm and think your way out rather than panicking and making things worse. The "remember the mule" story has been used in motivational speeches and self-help contexts for exactly this reason.

It's also benefited from truthiness—it sounds like it could be true because mules do have a reputation for being more level-headed than their donkey parents. But reputation isn't science, and metaphor isn't fact.

The Real Survival Advice

If you ever find yourself in quicksand (which is increasingly rare, given that most "quicksand" you encounter is shallow), here's what actually works:

• Don't panic or make sudden movements
• Slowly lean back to distribute your weight over a larger surface area
• Make slow, small movements to create space for water to flow in and loosen the suction
• Work your legs free gradually—this can take time but it works

Notice something? This advice applies whether you're a human, a donkey, a mule, or any other creature. Physics doesn't care about your species—it cares about density, surface area, and movement.

So while the donkey-and-mule story makes for a charming parable about the virtues of staying calm, it's best filed under "inspirational fiction" rather than animal behavior science. The real lesson? Don't believe everything you read on trivia lists—even when it involves adorable farm animals.