SwRI’s dog-detection system uses cell phones to collect video of unrestrained dogs. The automated system then analyzes their health and behavior to characterize whether they are strays or owned pets roaming the streets.
Courtesy of SwRI
Southwest Research Institute workers will soon cruise around San Antonio with cell phones strapped to their car windows, on the hunt for stray dogs.
Software that the San Antonio research nonprofit developed will shoot video and use artificial intelligence to tally up the multitudes of dogs wandering San Antonio streets.
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A stray dog walks along a path over the Apache Creek during sunset Wednesday, March 4, 2026, in San Antonio.
Andrew J. Whitaker/San Antonio Express-News
Engineers are relying on a branch of AI known as “computer vision” technology to capture images of dogs and try to determine whether they’re strays or roaming pets.
SwRI engineer Michael Koets said this type of AI is an older, less powerful version than what people are familiar with. This technology was developed over the past decade to recognize objects such as vehicles, trees and dogs, but it’s not the sophisticated version of AI that underpins well-known platforms such as ChatGPT and Claude.
“It is not perfect, I’ll give you that, but it is quite good,” Koets said of the software SwRI researchers developed to count dogs in San Antonio.
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“Nine times out of 10, it’s going to be accurate,” he added. “We do manually review the data to make those fine distinctions between a dog that seems in good health or ill health, and we have the ability to detect the presence of a person nearby, which is sort of a clue about whether or not this dog is out for a walk with its owner on a leash or wandering freely.”
Koets and other SwRI engineers will sift through its findings as work gets underway this month and develop a report for Animal Care Services by year’s end.
The phones will only capture and retain videos with dogs in them, Koets said, and SwRI will turn over the footage to the city at the end of the year.
The institute will collect footage within 32 census tracts that a team of researchers zeroed in on for a separate 2019 study on unrestrained dogs.
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ACS is paying SwRI about $100,000 to study the problem anew.
The previous study, conducted by a former ACS advisory board member and scientist at a local biotechnology company, estimated that more than 34,000 unrestrained dogs roamed San Antonio streets at any time and that more than 90% of them probably had owners.
Dogs were classified in the study by their physical characteristics and behavior. Stray dogs tend to be malnourished, have unkempt fur and don’t have collars. Roaming dogs usually look well-fed, have cleaner fur and may welcome contact with humans, according to the 2019 study.
Southwest Research Institute is using a cellular phone mounted on a vehicle to gather video of unrestrained dogs. Then SwRI-developed software detects and categorizes dogs as “stray” or “roaming,” to characterize whether dogs are truly strays.
Courtesy of SwRI
The number of strays has long concerned city officials. The 2019 study said the city wanted to know how many dogs were loose in the city in hopes they could learn whether increases in spay and neuter surgeries had reduced the population.
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But concern over strays has exploded in recent years.
ACS has been criticized in the wake of a 2023 string of gruesome and sometimes deadly dog attacks, which often involved violent pets escaping their yards and injuring neighbors or passersby.
The incidents brought attention to the city’s low call response rate and drew intense public backlash from fearful residents. At the time, the department was responding to only 44% of “critical calls,” which are those that concern aggressive dogs, animal neglect or cruelty, injured or sick animals and trapped or confined animals.
The city pumped millions of dollars into the department to beef up ACS officer response. The critical call response rate has risen to 94%, which is still short of the 100% rate the department had previously said it could hit by January of this year.
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The department also increased fines for owners whose dogs roam freely, ramped up its free spay-and-neuter program and launched an initiative that delivers pet food and items, as well as information on local laws, to neighborhoods across the city.
The new study will help officials gauge whether the city’s recent spending has helped cut down the number of dogs on the streets, ACS director Jon Gary said.
He suspects the situation has improved because other numbers are trending down. He said the city is getting fewer calls for help and workers are picking up fewer dead dogs from local roadways.
“We recognize we still have a long ways to go,” Gary said. “But I do think that there’s significant progress being made.”
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Before SwRI approached ACS with its dog-spotting technology, ACS tried and failed to replicate the 2019 study earlier this year.
The department paid almost $100,000 for St. Mary’s University and the University of Texas at San Antonio to review data manually collected by volunteers, but researchers determined the information was insufficient to properly estimate the number of stray and roaming dogs.
Gary said the volunteers drove around and took notes on paper on dogs they saw.
The 2019 study also relied on volunteers taking handwritten notes and photographs of dogs they came across. But that process went more smoothly because the group of volunteers was largely made up of partners in animal welfare organizations that knew what to look for, ACS spokeswoman Lisa Norwood said. The latest attempt at a manual count relied heavily on volunteers from the general public.
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City staff announced the latest study at a recent meeting of City Council’s Public Safety Committee.
Councilman Jalen McKee-Rodriguez, a committee member, asked staffers to develop a plan to slash the number of roaming and stray dogs, calling their presence on city streets a “health crisis.”
“It’s dangerous for so many people,” he said.