vipera berus common european adder, or viper is a venomous snake an s- to prepare for a strike in forest

adder animal background berus black brown colour common crossbar dark darker dorsal environment european eye fear flank forest grass green ground head hunter leaf leaves longitudinal markings nature outdoor pattern poison prepare rattlesnake reptile serpent snake spots sshape streak strike summer tail threatened venomous viper vipera widespread wildlife zigzag