A man puts a sun hat on a New York horse in 1907. Picture: Library of Congress.

Washington - The concern about overheated animals isn't new - it dates to the early years of the American animal protection movement.

At that time, however, fledgling activists were not as worried about dogs. Instead, they focused on urban horses.

When Henry Bergh founded the American Society for the Prevention of Cruelty to Animals (ASPCA) in 1866, its seal depicted an angel, sword at the ready and hand raised in protest as a teamster goes to beat his horse. In that pre-automobile era, horses were public animals, seen daily by urbanites as they pulled milk wagons and omnibuses. Millions of the animals lived in US cities by the turn of the 20th century, and signs of them were everywhere - in hitching posts that dotted sidewalks, livery stables that took up entire blocks, and in the stench of manure piles and equine carcasses that soiled the streets.

"An urban banker encountered more horses on a daily basis than a cowboy in Montana," Ann Norton Greene, a University of Pennsylvania historian who wrote a book about working horses, said in an email.

Although homeless dogs were also a focus of animal protection groups, most "were initially reluctant to jump headlong into dealing with stray dogs because they were so overwhelmed with their work with laboring animals" like horses, according to University of Texas historian Janet Davis.

Summer's stifling heat made conditions for workhorses difficult, often causing them to falter. In July 1905, 148 horses died in Washington alone, according to a news report from the time.

Activists offered hose-downs and advocated that drivers switch to summer-weight harnesses. In 1902, a music event at the Shoreham hotel in Washington raised money for equine water fountains. In Boston, one fountain design boasted individual drinking basins to limit disease. (A dog watering area was just beneath.) In 1910, the New York Women's League for Animals opened a water station that watered 80 to 85 horses an hour. Signs asked that drivers remove bits from their horses' mouths so they could drink in comfort.

The need for hydration was associated with both human and animal concerns, said Davis, an American studies and history professor at the University of Texas who authored a book about the animal welfare movement. Animal advocates in the Gilded Age and Progressive Era also campaigned for temperance.

"Both pushed for the establishment of public water fountains, which cooled thirsty humans who might otherwise seek refreshment at a saloon, and they lobbied for the construction of separate horse fountains," she said in an email.

Horse clothing further blurred horse-human lines. Toward the end of the 19th century, the idea that horses should wear human-style hats for protection from the summer heat gained traction, particularly in European cities such as Berlin, London and Paris. Many teamsters had already been fastening sponges, soaked in cool water, to their horses' heads. But by July 1899, New York stores featured fully-fashioned horse hats in their windows. The most common model was a peaked straw with a red tassel. The animals' ears poked through holes on either side.

By 1902, horse millinery had moved beyond the utilitarian into the fashionable. You could buy your horse a hat made out of canvas, stretched over a millinery frame, with a flynet. Driving and saddle horses wore Peter Pan hats, yachting caps, and bonnets known as mob caps. There were also sunbonnets for mares and baby bonnets for childrens' ponies. "I suppose I'll be buying a Panama for Dolly next season," one horse owner told The Washington Post in 1902.

What the horses thought of all this is unclear, but people had ideas. One horse wore a "shade bonnet" trimmed with a red and yellow quill at an angle, which "gave its unconscious wearer a most rakish air," the New York Times reported in 1906. A Post reporter in 1908 saw an older horse with a red braid-trimmed hat and a "patient face [that] looked out with an expression so shame-faced that pedestrians could not refrain from smiling." One didn't seem to mind being mocked for his velvet and violets-trimmed hat, the Washington Times noted in 1907: "He never even frowned when an old man called out, 'That's a becoming bonnet you have on, old lady!' But just think of the teasing he must have to stand from the other horses!"

Not everyone thought the hats were helpful or amusing, though. An opponent of horse headgear wrote a letter to the New York Times' editor in 1901, saying that the hats were unhealthy, so closely woven that they didn't allow in enough air, and the sweat couldn't evaporate. A 1909 French study found that hats actually made horses hotter; bareheaded horses standing in the sun had lower body temperatures than ones wearing hats.

In 1914, the Thoroughbred Record admonished owners to abandon hats. But by then, it didn't matter as much. Horses were yielding city streets to cars. Between 1910 and 1920, the number of urban horses in the United States halved, according to Greene's book, "Horses At Work."

Some of the few horses still left on the city street today pull carriages in Manhattan, and they have long been at the center of a controversy. Activists want them banned; carriage drivers argue that they provide jobs, attract tourists and are well cared-for. Blazing summer temperatures play a part in this, too.

"Certainly," said Greene, "concern about horses in the heat is used to support the argument against carriages."

But in the animal protection world, concern about the danger of workhorses overheating has given way to the plight of harder-to-spot dogs.

"Urban horses were on the street or in stables, not in enclosed metal boxes," said Greene, referring to the cars that today can act as death traps for dogs and other pets. "The meaning and function of animals has changed as well."