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McALLEN (Texas Tribune) — It’s been more than 50 years since the South Texas ocelot — a medium-sized spotted wildcat known for parallel stripes running down its neck — was put on the federal endangered species list.
By official counts, there are only about 100 of these creatures remaining in their native South Texas, concentrated in Cameron and Willacy counties, on the state's eastern coast.
So when two conservation groups learned that DNA from a male ocelot killed in 2021 by a motorist dozens of miles away in Hidalgo County suggested a previously unknown population of the animals, they celebrated.
“The results suggest that this cat possibly occupies a region of South Texas not yet known to ocelot researchers,” Sharon Wilcox, senior Texas representative for Defenders of Wildlife, said in a statement. “Hidalgo County may have more ocelots present in its more remote sections where appropriate habitat and access to prey exists.”
Ocelots once roamed much of South Texas. According to Texas Parks and Wildlife, records indicate that the ocelot lived in the southern Edwards Plateau Region and along the Coastal Plain. However, the population declined due to the erosion of its natural habitat, hunting and road deaths.
The decline has led to the dwindling of their contribution to the local ecosystem — typically dense thorny shrub land in the Rio Grande Valley — in which they hunt for rabbits, small rodents, and birds, keeping those populations in check.
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However, some scientists warn it might be too soon to celebrate.
Dr. Mike Tewes, a biologist with Texas A&M University-Kingsville who has studied ocelots for 42 years, said the DNA analysis did not provide enough evidence to conclude the range of ocelots was expanding in South Texas. He cast doubt on the announcement from the Friends of Laguna Atascosa National Wildlife Refuge and Defenders of Wildlife last week.
Tewes said the only conclusive piece of information that came out of the analysis is that the ocelot was unlikely to have been a captive cat.
"I would be extremely cautious of trying to make any other generalizations or summary beyond that," Tewes said.
Throughout his time studying ocelots, Tewes said, there have been numerous cases of what he calls "frustrated dispersals" which is when an ocelot leaves its population and travels some distance — typically 10 miles or fewer, though they can travel as far as 25 to 30 miles — and eventually are killed on the roads.
"I'd be very cautious of saying, even suggesting, this population is expanding based on this one roadkill over the past 40 years," Tewes said.
But Dr. Tom deMaar, a wildlife veterinarian in the Rio Grande Valley who was part of the team that received the genetic information of the ocelot, believes that there are multiple possibilities to explain the cat's DNA.
The ocelot was discovered just north of Edinburg along Highway 281, about 50 miles from where wild ocelots are known to reside in the state. Scientists determined the ocelot suffered blunt force trauma, likely caused by being hit by a vehicle. DNA samples were finally tested in January.
During DNA testing, scientists look for genetic markers. Within the Texas population, ocelots have seven unique markers and this animal had all seven, according to deMaar. However, the ocelot also had two markers found in the Mexican population.
He said those results lay out three possibilities.
Echoing Tewes, deMaar said the ocelot could have dispersed from Mexico but thinks this scenario unlikely as the animal would have had to traverse Reynosa, Pharr, Edinburg, McAllen, and possibly other areas along the Texas-Mexico border region.
The second possibility is the cat represents a population researchers have not yet recognized and that retained some Mexican DNA.
Lastly, deMaar said it's possible these Mexican markers do already exist in the Texas population of ocelots and those markers have just gone undetected.
Laura De la Garza, a biologist with the U.S. Fish and Wildlife Service, said more information is needed before reaching any kind of conclusion.
She agreed with Tewes' reluctance to suggest the ocelot range could be expanding and said scientists and agencies needed to continue to work together to learn more.
"As we share information, we're going to get answers to this and this is where we have to be very careful about what we're putting out to folks out there," De la Garza said. "We have to be very careful and give educated answers because we want to make sure that we're doing our due diligence for the species and that we're in no way taking away from that recovery, from that conservation, but adding to it."
Earlier this year, the U.S. Fish and Wildlife Service signed a safe harbor agreement with the East Foundation, an organization that owns and manages ranch land in South Texas.
Through the agreement, participating landowners will allow ocelots to use the habitat on their land and cooperate with the foundation to allow ocelot monitoring.
Wilcox, of the Defenders of Wildlife, said in an interview with The Texas Tribune that the results challenged them to think expansively about those conservation efforts.
"Ocelots are holding their last stand against human development occurring at unprecedented rates in South Texas," Wilcox said. "These cats need wild spaces and places to roam and this documented sighting of this cat gives us hope that they are holding on in the wildest corners of our region."
The challenge before them now, she said, is to protect the habitat that remains while restoring it in places that could connect ocelot groups in Texas, giving the cats that space to roam.
"Ocelots are emblematic of this region and their struggle to survive in the wildest margins represents a larger struggle to preserve native landscapes in South Texas," Wilcox said. “With open spaces rapidly disappearing, the plight of the ocelot speaks to far greater issues concerning development and loss of wild places throughout Texas."
Reporting in the Rio Grande Valley is supported in part by the Methodist Healthcare Ministries of South Texas.
Disclosure: Texas A&M University has been a financial supporter of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune's journalism. Find a complete list of them here.
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This article originally appeared in The Texas Tribune at https://www.texastribune.org/2024/04/25/south-texas-ocelot-population/.
"Is the ocelot, the endangered South Texas wildcat, making a comeback?" was first published by The Texas Tribune, a nonprofit, nonpartisan media organization that informs Texans — and engages with them — about public policy, politics, government and statewide issues.
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