Every year on the first Tuesday of November, many Australians tune in to watch “the race that stops a nation”: the Melbourne Cup.Run at Flemington across 3,200 metres (two miles), the Melbourne Cup dates back to 1861.It’s one of the world’s richest races, with A$10 million in total prize money on offer this year.The fastest winning time at Flemington came in 1990, when Kingston Rule flashed home in 3 minutes 16.3 seconds – an average speed of 58.7 kilometres per hour.The highly trained thoroughbreds that compete are considered the best of the best in world racing. But are they really top of the tree in the broader animal kingdom?As an evolutionary biomechanist specialising in the relationship between form, function and ecology of living and extinct animals, I ran the numbers to find out, comparing the fastest land animals in the world across 3,200 metres.The maths behind the predictionsTo compare thoroughbreds with different species in this hypothetical race, we need to estimate a few variables.The first is the maximum steady speed an animal can maintain. In the scientific literature this is known as “critical speed”. At this pace, animals should be able to run around the track easily.When sprinting, though, animals can only maintain a maximal effort for a short distance or time. This is called the “distance reserve”.Using these values we can make some good guesses about how long different animals might take to run the 3,200m race, based on a formula designed by exercise physiologist Mark Burnley. The formula looks at the time to run the race, the distance of the race, the distance reserve and critical speed.For a full breakdown of the calculations used in the below predictions, check them out here. Let the race beginLet’s start off by looking at us humans. We can use marathon world-record pace as a practical stand-in for critical speed. The men’s world record marathon time was set by Kelvin Kiptum in 2023, who completed the 42km event in 2 hours 35 seconds, an average of 21km per hour. Based on my formula, the best male runner would finish the Melbourne Cup in about 8 minutes 19 seconds (the fastest woman would take about 9 minutes 6 seconds).That’s elite by any track standard but nowhere near the Melbourne Cup’s equine averages.Of course, humans aren’t even the fastest animals on two legs, so what if we swapped sneakers for talons?The ostrich brings a different kind of stride to the starting gate.The ostrich is the world’s fastest biped, can run over a broad range of speeds, and is exceptionally economical, thanks to long tendons and elastic energy storage. In 2016, researchers at the Royal Veterinary College in London tested the running speed of ostriches by putting tiny backpacks containing high-speed GPS units on them, then chasing them around a paddock with a quad bike (yes, really). They found the top speed of ostriches was about 41km/h but the most preferred speed (when undisturbed) was 15.7km/h.Conservatively, my prediction would be an ostrich finishing the Melbourne Cup in about 9 minutes 5 seconds.That’s not far off what humans could do, but still off the pace of horses. We need something faster.The cheetah is the ultimate sprinter – but can it go the distance? Using the same backpack from the ostrich study, the same research group headed to Africa to collect data on cheetahs hunting in the wild. A remarkable top speed of 93km/h was recorded. Yet the typical mean top speed was around 54km/h and the longest hunting chases rarely exceeded about 500m before the cheetah either caught or abandoned its prey.Rearranging our model and plugging it into the Melbourne Cup equation gives a predicted 3,200m time of around 9 minutes 30 seconds – worse than humans and ostriches!We need something with more staying power.Let’s try out an Aussie favourite.Kangaroos are endurance oddballs: at some point in the 1970s, researchers managed to train a kangaroo to hop on a treadmill while wearing a metabolic mask.This now classic lab experiment showed red kangaroos hop with remarkable efficiency for sustained speed. This comes from their extreme elastic energy recycling in the hindlimb tendons, combined with their unique hopping gait.While this research shows kangaroos’ critical speed is about 23.4km/h, peak speed estimates are harder to find. Various unverified sources exist online that estimate it to be around 60–65km/h.Using these estimates, I predict the kangaroo would be able to finish the Melbourne Cup in about 6 minutes 35 seconds. That’s much better than humans and ostriches, but still well behind the horses.Few animals are as specialised for high-speed sprinting as the greyhound.Track data show elite racers reaching speeds of about 68km/h over 500m, with longer “stayer” races (700–950m) run at average speeds of about 56km/h.Laboratory treadmill studies report these dogs can only sustain their highest pace for about a minute. Using stayer-distance race records only, and again using the aforementioned formula, the fastest greyhound would finish the Melbourne Cup in about 4 minutes 7 seconds.That’s impressively close to the Melbourne Cup record. However, greyhounds rarely run more than 1km – their sprint-adapted muscle fibres lead to rapid heat build-up and fatigue, suggesting even this might be a generous estimate.So, it appears thoroughbreds are in a class of their own. Maybe we need to find another competitor more horse-like.In the 2005 cinematic masterpiece “Racing Stripes”, Stripes, an abandoned circus zebra competes in and (spoiler alert) wins the Kentucky Open.Could a wild zebra beat our Melbourne Cup field?In a 2018 study, researchers fitted GPS collars on seven zebras (and other species), gathering 1,801 runs from zebras. They found zebras had significantly lower maximal muscle power and acceleration than their lion pursuers. They estimated a burst speed of about 54km/h and a conservative sustainable pace of about 26.5km/h.Plugging this into our model gives a 3,200m estimate of about 8 minutes 8 seconds. It’s respectable for a grazing ungulate but far behind elite stayers.And the winner is …So the science has spoken and the results are in. The Melbourne Cup thoroughbreds easily win this race against most other running species. The greyhound finishes second if it can hang on, and the kangaroo comes home in a respectable third place. We’d then have to wait about two minutes for the next group to come in with the humans, zebras, ostriches and cheetahs all finishing around the same time.Christofer Clemente does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.