areas are well known for several  threatened  and  endemic  species including Tiger ,  Nilgiri Tahr ,  Grizzled Giant Squirrel ,  Nilgiri Wood-pigeon ,  Elephant ,  Gaur ,  Sambar Deer ,  Purple Frog  and  Neelakurinji . [3] [4] Idukki is known for its green mountains, streams and spices. [ citation needed ]