To Xanthos' claim that the horses were being overworked during the busy holiday season, Hughes said only weekends were unusually busy, weather permitting, meaning "only six busy weekends a year, between Thanksgiving and New Year's."
Malone said operators -- many of whom have grown up and worked with horses their whole lives -- embody an ethic that clashes with the image their critics promote.
"Operating a carriage is a life choice more than a livelihood," he said. "It's not what we do -- it's who we are."
Rose Nolen-Walston, an assistant professor of equine medicine at the University of Pennsylvania School of Veterinary Medicine, said "more horses hurt themselves playing in the field than on city streets."
"New York is not an intrinsically dangerous place for a horse to be as long as appropriate precautions are taken," she said.
The "big caveat" she appends is, "Regulations are only as good as their enforcement."
She said she could not evaluate New York's enforcement but wondered how well-funded it was given the economy. "It's a tricky time for budgets, isn't it?" she said.
As to horses' "psychological well-being" and whether they "enjoy" pulling carriages, Nolen-Walston said while it's "impossible to know exactly what they're thinking ... it's almost impossible to make a horse do something it doesn't want to do."
Many horses in the United States work for humans and have high standards of living, and New York City isn't necessarily an exception, she said.
"Would it be ideal if the carriage horses were turned out every night? Sure, but there's no evidence to suggest it's inhumane for horses to work in urban environments if they have periodic breaks," she said.
Five weeks a year -- the New York City requirement -- seemed good, she said, adding no one had researched what the ideal schedule for urban horses would be.
New York Mayor Mike Bloomberg has been a strong defender of New York carriage rides, saying horses are well cared for -- and many might not be alive if they didn't pull carriages.
Elaine McMinn, owner-operator of Greyhorse Carriage Company, in Allentown, N.J., said this was "probably" true: "[Carriage operators] are among the only people buying horses nowadays."
Nolen-Walston wrote in an email: "There is a huge problem with unwanted horses in this country right now." Giving New York carriage horses a "fair working life and [treating them] humanely is a small, but useful step in preventing more horses from joining this number."
Nolen-Walston, seeking to put the debate in historical perspective, said horses have been working with humans for hundreds of years. The exhaust fumes and concrete of modern cities that urban carriage horses contend with are more than balanced out by changes in us, specifically the rise of the animal welfare movement, she said.
"A hundred years ago, nobody cared about horses' [collective] well-being," but now there are detailed regulations -- however well they're enforced -- safeguarding it, she said.
"Activists have had a huge role in this and should be commended," she said.