The Colubrids make up the largest snake family in the world.  The family 
is highly variable and often individual species vary greatly in colour 
across their range making identification difficult without resorting to 
such characteristics as scale patterns.

In general Canadian Colubrids fall into one of three broad classes: 
striped, blotched, or unpatterned snakes.  To complicate matters, 
some striped snakes have spots (but not large blotches) and some 
snakes are largely unpatterned but may have faint stripes.  

One feature which varies among many species of snakes in this family 
is the number of scale rows.  With a snake in hand it is quite straight 
forward to count the scale rows as illustrated below is
viewed from the top.  The scale rows can be counted from either the
left or right, starting at the belly scales.  The belly or ventral
scales are not counted.

  
  
  
     
Another other feature that is useful in identifying snakes is the
anal plate, which is either single or divided.  The anal plate
marks the beginning of the tail and can be found on the underside
of the snake.

  
  
  

Because of the variability in patterning, if the snake in question is not 
found in one group try another.