The wide range of elevations and rugged topography of the massif create diverse habitats that transition quickly with changes in altitude. Warm, dense rainforest can be found at lower elevations, followed by shorter forests at higher elevations, followed still by cloud forest, and topped near the peaks with the only remaining undisturbed mountain scrub in Madagascar. Better growing conditions for plants can be found on the eastern side of the mountains, which receives more rain than the western side. This habitat diversity lends itself to high levels of biodiversity. At least 118 species of bird, 148 species of reptile and amphibian, and 11 species of lemur are known to occur within Marojejy National Park. One of the lemurs, the silky sifaka (Propithecus candidus) is listed among The World's 25 Most Endangered Primates. The helmet vanga (Euryceros prevostii) is considered the iconic bird species of the park.