bullsnake (catenifer ssp. sayi) slithering through colorado forest undergrowth

crawling ground pituophis catenifer animal biology black bullsnake colorado forest constricting constrictor daytime decomposing ecology environment fauna flora floor harmless head herpetofauna herpetology leaves movement natural nature venomous outdoor outdoors patterned predator prey reptile sayi scales slithering snake ssp terrestrial twigs undergrowth white wild wilderness wildlife winding zoology