Random Lake Sturgeon Fact: The sturgeons are primitive fishes whose fossil history can be traced back for fifty million years. Instead of overlapping scales, they have five lengthwise rows of heavy bony shields and a head covered with bony plates. The rest of the skeleton is cartilage or gristle, as in the sharks. Also like the sharks, the spinal column continues into the upper lobe of the tail. On the underside of the snout are four fleshy barbels or feelers that drag the bottom and locate the snails, clams, crayfish, worms and insect larvae on which it feeds. Behind these is the tube-like mouth which sucks up food like a vacuum cleaner.