As prehistoric as they look
Lake sturgeons appeared in the fossil record 136 million years ago. They haven’t changed much since then. A heavy, torpedo-shaped body is partially covered with bony plates instead of scales, while the skeleton is cartilage instead of bone. Four long barbels that sprout from a blunt snout help these bottom-feeding omnivores sweep for insects, crustaceans, small clams, snails and anything else they can suck into a retractable tubular mouth. Electroreceptors on the head, called ampullae of Lorenzini, sense weak electric fields from prey or potential mates.
Long-lived, yet endangered
The oldest documented lake sturgeon was 154 years old, and it was most likely a female. More typical age ranges are 50 years for males and 75 for females. Such long-lived species are slow to mature. Males reach breeding age at 8 to 12, while females are between 14 and 33 before they start laying eggs. Overfishing has been a double whammy for sturgeon populations: Too many have been taken, and many never had the chance to reproduce. Other threats include dams that block spawning migrations. Lake sturgeon are now protected as endangered species in Illinois and Indiana.