An eight to 10-feet-long prehistoric salmon species called Oncorhynchus rastrosus stalked the seas and streams of the Miocene period. It weighed upwards of 400 pounds and had a formidable pair of front teeth that projected out from the sides of their mouths like tusks. This major dental update is detailed in a study published April 24 in the open-access journal PLOS ONE. Scientists are not exactly sure what these signature tusks were used for, but believe they were primarily used to fight off other salmon or predators.