Once considered a fish version of a saber-toothed tiger due to its large, backward-pointing teeth, the largest known salmon species, Oncorhynchus rastrosus, has now been reimagined as more closely resembling an aquatic warthog. This revised understanding emerged from the analysis of newly discovered, more intact fossils, which revealed that the salmon’s teeth projected sideways, resembling tusks rather than fangs. This finding has prompted paleontologists to reconsider the nickname “saber-toothed salmon,” which had been based on earlier, incomplete fossils that were essentially lying flat and scattered.
The intact fossils, found in an extinct river that is part of the Columbia River Basin, provided a more comprehensive view of the salmon’s anatomy. Researchers analyzed the fossils, performed CT scans, and compared them to earlier specimens. This thorough examination revealed that both male and female salmon possessed tusks, which scientists believe were primarily used for defense. The salmon’s massive size and tusks may have served as deterrents against predators in the open ocean or as a means of defending their nests in the river. The salmon’s tusks may have also served as shovels to dig nests in the riverbed.
While the tusks were likely used for defense, they were not used for eating. Oncorhynchus rastrosus was a filter feeder, straining plankton through a mesh-like structure in its mouth, eliminating the need for teeth for chewing. Paleontologists are now investigating why salmon eventually lost their formidable teeth, speculating that the tusks may have been an evolutionary experiment that ultimately proved unnecessary for the survival of Pacific salmon as a larger group.
