In the 16th century, folks kept dogs around more for function than form, shepherding sheep, sniffing out game and warming up chilly laps. Also around that time, a certain breed of dog found a role as the culinary workhorse of large kitchens.
Enter the turnspit dog. Known for its long, stocky body and short legs (like fluffier Dachshunds), these pups kept upper class Elizabethan meats a-turning in the hearth.
Before the arrival of the automated spit, roasting meats had to be cranked continually by hand for evenness. Then someone figured out you could put a dog on a treadmill, attach the rotating wheel to a spit, and accomplish the same thing. This canine innovation was hailed as big improvement, as suggested in a 1576 description of how the pups would spin the roasting meats "by a small wheel, walking round it and making it turn evenly in such a manner that no cook or servant could do it more cleverly."
Turnspit dogs weren't a flash in the pan either. Their breeding continued for a couple centuries, and they made the trek from Britain to the United States as well since they were handy for more than just roasting meat. As Stanley Coren explains in The Pawprints of History: Dogs and the Course of Human Events, people applied the rudimentary treadmill tech to other domestic tasks, including churning butter, pressing fruits, pumping water and milling grain.
But working conditions, especially in kitchens, weren't so great for turnspit dogs, which was part of what compelled Henry Bergh to start the American Society for the Prevention of Cruelty to Animals in 1866. Bergh saw the turnspit dogs' treatment as tantamount to slavery, as they were forced to trot next to blazing fires for hours at a time without access to water. Cooks might even toss hot coals onto the treadmill platform to enliven weary paws. Due to the labor intensity, many turnspits would work in pairs and trading off on the meat-spinning hamster wheel, and some think that dreadful tag-team is origin of the phrase "every dog has his day." Even on Sundays, the dogs couldn't catch a break when their owners often took them to Church to serve as foot warmers.
No wonder Bergh and his early ASPCA fought against turnspit dog labor; he was known to storm New York saloons where the laboring dogs would be powering cider presses and threaten legal action against the proprietors. Technology though would ultimately unleash turnspits -- and lead to the breed's extinction. With the invention of the automated roasting jacks in the mid-19th century, the hot dogs simply were no long needed.