A greyhound explodes off the starting line, legs pumping, ears pinned flat, chasing a mechanical rabbit around the track. In just three strides, she's already faster than you can sprint. By the time she hits full speed — seventy kilometers per hour — she's moving faster than a car in a neighborhood street. How does she do it? The answer is written into every inch of her body, from her nose to the tip of her tail.

Start with the engine: the heart and lungs. A greyhound's heart is enormous for her size — about the size of a grapefruit, much bigger than most dogs her weight. It pumps oxygen-rich blood like a fire hose. Her lungs are huge too, filling her deep chest. Every breath she takes floods her muscles with fuel. It's like having a V8 engine in a sports car — more power than the frame seems built to hold.

Now the frame itself. A greyhound is built like an arrow. Long, narrow skull. Thin waist. Deep chest that houses those massive lungs, then a tuck-up belly that keeps her light. Every ounce of extra weight has been stripped away — even her skin is thinner than most dogs'. She's aerodynamic, slicing through the air with almost nothing to slow her down.

The legs are where it gets wild. Greyhounds have long, springy legs with tendons like steel cables. When she runs, she doesn't just push off the ground — she compresses those tendons like springs and then releases them, catapulting forward. Watch her in slow motion and you'll see something strange: for a moment, all four feet leave the ground. She's flying, suspended in mid-air, before the front paws touch down again and launch her into the next bound.

That flying leap is called a double-suspension gallop, and it's the secret to her speed. Most dogs gallop with one moment of suspension per stride. Greyhounds have two — one when the legs are extended, one when they're gathered. It means she spends more time in the air and less time slowed by the ground. Each stride covers seven meters. She's not running; she's bounding like a kangaroo on fast-forward.

The fuel system is just as specialized. Greyhounds have a type of muscle fiber called fast-twitch — the same kind sprinters have. These fibers contract explosively, generating huge bursts of power. But they burn out quickly, which is why greyhounds are sprinters, not marathoners. After thirty seconds at top speed, she's winded. She's built for the chase, not the cross-country run.

Even her blood is different. Greyhounds have more red blood cells than most dogs — up to twice as many. Red blood cells carry oxygen, so more cells mean more fuel delivered to those fast-twitch muscles. It's like having a turbocharger. After a race, her blood is so thick with cells that vets have to account for it when they run tests. Her whole body is dialed to eleven.

Put it all together — the massive heart, the arrow body, the spring-loaded legs, the double-suspension gallop, the explosive muscles, the supercharged blood — and you have a dog built by centuries of selection to do one thing better than any other: run like the wind. Greyhounds aren't just fast. They're a masterpiece of speed, every part working in perfect harmony. And when she crosses the finish line and slows to a trot, panting and happy, she's already dreaming of the next chase.