Ключевые слова: adder, agile, america, animal, arboreal, arenal, asia, asian, berus, camouflage, captive, central, climber, common, controlled, costa, defensive, display, dweller, eurasia, eurasian, europe, european, fauna, forest, leptophis, life, mexicanus, natural, nature, one, or, parrot, position, rearfanged, reptile, reptilia, satiny, serpentes, situation, snake, squamata, threat, viper, vipera, viperidae, viperinae, wild, wildlife, zoo,