Sturgeons are one of the oldest groups of fishes. Sporting an armor of five rows of bony, modified scales called dermal scutes and a sharklike tail fin, this group of several-hundred-pound beasts has survived for approximately 160 million years. Because their physical appearance has changed very little over time, supported by a slow rate of evolution, sturgeon have been called living fossils.
Despite their survival through several geological time periods, many present-day sturgeon species are at threat of extinction, with 17 of 27 species listed as “critically endangered.”
