In 2021, an animal resembling a dog was found run over on a road located in the municipality of Vacaria, in Rio Grande do Sul.
The female was rescued still alive by biologist Herbert Hasse Junior, in partnership with the city’s environmental patrol.
In a first analysis, the specialist identified the victim of the traffic accident as a wild species.
She was taken to the veterinary hospital at the Federal University of Rio Grande do Sul (UFRGS), which has a team specialized in dealing with cases like this.
And that’s when this story took its first twist. When removing the injured animal from the transport box, researcher Flávia Ferrari observed that it was very different from the wildcat.
This species, similar to a fox, has beige and gray fur and is endemic to South America, especially in areas of Argentina, Uruguay, Paraguay, Bolivia and the southern region of Brazil.
It is worth noting that, despite being popularly called fox, it is a different species.
The animal was then transferred to the kennel, which handles domestic species.
That’s when the second surprise came. This individual’s behavior was not at all similar to that of a dog.
He completely refused to eat food, for example.
The caregivers then decided to do an experiment and offered small rodents to the mysterious canine. And he ate it without blinking — as expected from a wild gourd.
With the discovery, the victim of being run over was sent once again to the wild animal sector.
The doubt remained even when geneticist Thales Renato Ochotorena de Freitas, from the UFRGS Biosciences Institute, was called upon to give an opinion.
“The first thing that caught my attention was the color of the coat, which was quite dark. He also barked like a dog”, recalls the scientist.
Cape Graxains are known to emit a short, high-pitched whine.
In short: the animal ate like a wild prawn, but barked like a domestic dog. After all, which species did he belong to?
To answer this question definitively, Freitas selected two other experts.
The first of them, cytogeneticist Rafael Kretschmer, from the Federal University of Pelotas (UFPel), was tasked with searching the animal’s chromosomes.
It is worth remembering here that chromosomes are the structures that house all the genetic material of a living being. They are inherited directly from the parents — half from the mother, half from the father.
If the animal that was run over was a domestic dog (Canis lupus familiaris), it would have 78 chromosomes. Now, if it were a wildcat (Lycalopex gymnocercus), it would have 74 units of this structure.
“We did a skin biopsy and a cell culture [cultivo de células em laboratório]. When carrying out the analysis, we discovered that the animal had 76 chromosomes”, reports Kretschmer.
The only canid that appears in Rio Grande do Sul with this number of chromosomes is the maned wolf (Chrysocyon brachyurus), but scientists quickly discarded the idea of the individual belonging to this species due to its physical characteristics.
From this work, they came to another conclusion: the animal was not a dog or a prawn, but rather a mixture of both.
The unusual number of chromosomes could be explained by crossing between representatives of these two species. From the dog, 39 chromosomes came (half of the total). From graxaim-do-campo, 37.
The combination of the two reaches exactly the 76 chromosomes found by the laboratory in Rio Grande do Sul.
To confirm the finding, biologist Bruna Elenara Szynwelski, from UFRGS, carried out an analysis of the hybrid’s genes.
“The first thing we looked at was the mitochondrial DNA, which is inherited exclusively from the mother” points out the specialist.
Mitochondrial DNA is located outside the cell nucleus, separated from the rest of the DNA, in a structure responsible for generating energy — the mitochondria.
“And that’s when we observed that this individual’s maternal lineage was that of wild grass,” says Szynwelski.
By analyzing the complete DNA, the researchers discovered stretches of genes exclusive to dogs, and others that only appear in prawns.
From this, they were able to definitively conclude that the hit-and-run victim was a hybrid.
This was the first time that this phenomenon was described in detail in South America — there are similar cases recorded with other canids in Africa, Europe and North America.
The findings, published in the scientific journal Animals in early August, were classified as “rare” and “surprising” by those involved in the work. After all, despite belonging to the same family — the canidae — dogs and wildcats are relatively distant relatives on the evolutionary tree.
After recovering from the injuries caused by being run over, the canine was castrated and sent to Mantenedouro São Braz, a sanctuary and zoo based in Santa Maria, also in Rio Grande do Sul.
New twists and future learnings
Those involved in the investigation suspect that this same animal had been spotted on other occasions in the past.
In 2019, Hasse Junior — the same biologist who carried out the rescue in 2021 — spotted a strange-looking canid in the Vacaria region.
At the time, he recorded a video, and the team believes it is the same animal. This is because, in the records obtained in 2019 and 2021, it is possible to see a white spot on the chest of both animals.
But history had a third surprise in store for everyone involved.
One day after the interview with BBC News Brasil, held on August 29, UFRGS researchers sent an email with unexpected news.
“As soon as we finished the meeting, we called the sanctuary [o Mantenedouro São Braz] to request current photos of the hybrid,” the study authors wrote.
“Whoever responded informed us that the animal died about half a year ago.”
Scientists confirmed the information in a second interaction via WhatsApp with the zookeeper, but are still trying to understand what caused the animal’s death.
BBC News Brasil also tried to contact Mantenedouro São Braz via text messages, but no responses were sent until the publication of this report.
While they are still trying to discover what is behind the hybrid’s death, experts involved in the story are evaluating the possible impacts that crossbreeding between canine species could have.
“This phenomenon can be quite harmful, in different ways,” says Szynwelski.
“One of them is the adaptation of this animal in the wild. The wild cat’s color is very similar to that of its habitat, which allows it to camouflage itself when hunting and hiding from predators. The hybrid, which was born with dark fur, does not have this same attribute”, she explains.
“And there is a possible exchange of diseases between species. Domestic dogs can pass certain conditions on to wild animals and this can become a serious problem”, predicts Freitas.
“When we think about species conservation, we need to make long-term projections. And now we will explore and study all these questions from now on”, concludes Szynwelski.
By André Biernath