Study flags possible spinal nerve tumors in Smilodon fossils
Bottom line
A new Frontiers in Veterinary Science brief research report describes three Smilodon fatalis vertebral specimens from Rancho La Brea with foraminal widening, a skeletal change the author says is most consistent with a possible spinal nerve tumor. Reviewing 3,722 vertebrae and sacra representing 849 adult saber-toothed cats in the La Brea Tar Pits Museum collection, the study estimated a prevalence-like rate of 353 per 100,000 individuals. The paper argues that, while the fossil finding isn't directly comparable with modern clinical incidence, the signal appears unusually high and may fit with broader evidence that late Smilodon populations carried a heavy burden of developmental pathology. (frontiersin.org)
Why it matters: For veterinary professionals, this is less about diagnosing an extinct cat than about comparative pathology. The paper uses imaging patterns familiar from small animal and human medicine, where smooth foraminal widening along a spinal nerve's course is strongly associated with spinal nerve tumors, to show how veterinary radiology and oncology frameworks can illuminate disease in fossil populations. It also adds to a growing La Brea literature linking skeletal disease, congenital malformations, and possible inbreeding in large carnivores, with relevance for how clinicians and conservation veterinarians think about genetic bottlenecks in modern species. (frontiersin.org)
What to watch: Whether future La Brea pathology studies, or advances in biomolecular work on asphalt-preserved fossils, can test the inbreeding hypothesis more directly and show whether these lesions were isolated findings or part of a broader end-stage health pattern in extinct megafauna. (eurekalert.org)
Key facts
- Study type
- Brief research report
- Journal
- Frontiers in Veterinary Science
- Publication date
- July 27, 2026
- Species
- Smilodon fatalis
- Site
- Rancho La Brea
- Finding
- Three lumbar vertebral specimens showed foraminal widening
- Interpretation
- Most consistent with a possible spinal nerve tumor
- Sample analyzed
- 849 adult Smilodon specimens
- Estimated rate
- 353 per 100,000 individuals
A study published July 27, 2026, in Frontiers in Veterinary Science reports possible evidence of spinal nerve tumors in the saber-toothed cat Smilodon fatalis from Rancho La Brea. Author Hugo Schmökel identified three lumbar vertebral specimens with foraminal widening, a bony change that in living patients is usually linked to slow-growing tumors such as schwannomas or neurofibromas affecting spinal nerve roots. Across 849 adult individuals represented in the museum database, that translated to a prevalence-like estimate of 353 per 100,000. (frontiersin.org)
The finding fits into a longer-running effort to use La Brea's unusually large fossil sample to reconstruct population health near the end of the Pleistocene. The tar seeps preserved abundant remains of Smilodon fatalis and dire wolves from the several-thousand-year interval leading up to the North American megafaunal extinctions around 12,000 years ago. Because the site contains hundreds to thousands of comparable specimens, researchers have increasingly used it to study not just anatomy and ecology, but also congenital disease, degenerative change, and trauma. (frontiersin.org)
In the new paper, Schmökel examined pathological vertebrae and sacra from multiple La Brea pits and excluded damaged and juvenile material, leaving 849 adult Smilodon specimens suitable for analysis. Three specimens, dated to roughly 28,000, 13,000, and 12,000 years before present, showed unilateral enlargement of lumbar foramina; two also had bone proliferations, and one had block vertebra formation. The author argues that the pattern is compatible with a slowly expanding spinal nerve tumor, while acknowledging a key limitation of paleopathology: no soft tissue survives, so the diagnosis can't be confirmed with biopsy or histopathology. (frontiersin.org)
The paper is careful about the comparison point. Reported human spinal nerve tumor incidence is far lower, at 0.22 to 0.38 per 100,000, but the author notes that a fossil prevalence-like estimate from a taphonomically biased assemblage isn't directly comparable to clinical incidence in living populations. Even so, the study suggests the lesions may be another marker of poor genetic health in a species already suspected of carrying a high load of developmental abnormalities. The discussion points to human NF1-associated tumor biology and to lineage effects reported in Danish Holstein cattle as examples of how inherited susceptibility can shape tumor patterns. (frontiersin.org)
That interpretation also lines up with prior Rancho La Brea work. A 2023 PLOS One study reported osteochondrosis dissecans-like subchondral defects in Smilodon fatalis and dire wolves, and outside experts told Live Science at the time that the pathology record offered a more holistic view of how disease and population stress may have evolved near extinction. La Brea researchers have also documented developmental disease in individual Smilodon skeletons, including CT-based evidence of hip dysplasia in a cat that survived to adulthood, a finding used to argue for possible social support within the species. (journals.plos.org)
Why it matters: For veterinary professionals, the study is a reminder that diagnostic logic developed in companion animal medicine can travel surprisingly well across disciplines. The lesion pattern here is being interpreted through the lens of veterinary imaging, spinal pathology, and oncology, turning fossil bone into a case study in comparative disease. More broadly, the inbreeding hypothesis, while still inferential, resonates with current veterinary and conservation concerns: when populations contract, clinicians may see more congenital anomalies, orthopedic disease, or neoplasia linked to reduced genetic diversity. (frontiersin.org)
There's also an important caution in the paper's framing. These were not clinical patients, and the collection is shaped by preservation bias, time averaging, and incomplete anatomy. That means the study doesn't prove spinal nerve tumors were common in Smilodon, only that three fossils show a pattern strongly suggestive of them. Still, in a pathology collection as deep as La Brea's, even a small cluster can raise useful questions about disease burden at a population level. (frontiersin.org)
What to watch: The next step is likely more comparative paleopathology from La Brea, along with any progress in extracting genetic or other biomolecular signals from asphalt-preserved material, which could help test whether inbreeding really underlies the lesion patterns now being described. (eurekalert.org)