Form and Function

The Polyodon spathula, or paddlefish, has one extremely distinguishing feature: its paddle-shaped, flattened snout (Paddlefish, 2011).  The snout is also generally very long; it can be one-third the length of its body.  It contains the electrosensory organs that help it find its prey (Paddlefish, 2011).  Paddlefish are primitive, that is, "relating to, denoting, or preserving an early stage in the evolutionary or historical development of something" (  The main indication that the paddlefish are primitive is that they have skeletons made of mostly cartilaginous material (Barras, 2013). Their tail fins are also turned upward (Paddlefish, 2011).  This is because the bone in their back extends into the upper lobe in the tail fin (Barras, 2013).  All paddlefish are the same gray color and can reach up to one hundred and fifty pounds and and six feet in length (Paddlefish, 2011).              


Paddlefish have smooth skin with very few scales.  This skin, covered in a slimy mucus, makes swimming more efficient (Barras, 2013).  The previously mentioned snout covered in electrosensory organs is very important, as paddlefish live in murky waters and need to be able to sense the plankton that they feed on (Barras, 2013). 

(For more about the paddlefish's nutrition, see our Nutrition page).