Invasive species are species that have been introduced into an environment to which they are not native and have since become a problem due to the spread and increase in population, causing harm often the plants and animals already present. Cervus elaphus (C. elaphus), also known as red deer or elk, is an invasive animal now found throughout South America and New Zealand (Flueck, 2010). Native to North America, Asia and Europe (hence the common name European Red Deer), Cervus elaphus was introduced less than a hundred years ago in Argentina and parts of New Zealand and has invaded national parks and natural forests. They have influenced native flora and fauna and disrupt their processes (Flueck, 2010). These red deer cause less regeneration of favored plants, which prevents the growth of normal vegetation, thus changing the structure and composition of the ecosystem in which they reside (Flueck, 2010). Now competing with native deer from Chile, Argentina and New Zealand, ecological concerns have been raised to save already existing native species as well as the canopy environment where they live. Without many descriptive characteristics, this red deer, with its plain brown body and lighter belly, contains many details about its origin and destination. C. elaphus is indigenous to Eurasia and North America, including Afghanistan, Belgium, Denmark, France, Sweden, the United Kingdom, and the United States (Lovari, 2008). They have been introduced to Argentina, Australia, Chile, New Zealand and Portugal, but are now starting to cause problems beyond what can be controlled. This species has spread to many areas, not for some unknown cause, but because C. elaphus is also on the endangered species list (Lo...... middle of article.. .... following control of invasive deer. Conservation Biology 17(2): 450-459.Flueck, WT 2010. Cervus elaphus (mammal). , Herrero, J., Maran, T., Giannatos, G., Stubbe, M., Aulagnier, S., Jdeidi, T., Masseti, M. Nader, I., de Smet, K. & Cuzin, F. 2008. Cervus elaphus In: IUCN 2010. IUCN Red List of Threatened Species. Merino, ML, Carpinetti, BN and Abbal, AM 2009. Invasive Mammals in the National Park System of Argentina. (1):42-49.Relva, A., Nunez, M.A. and Simberloff, D. 2010. Introduced deer reduce native vegetation cover and facilitate invasion of non-native tree species: evidence for invasions organic.. 12(2): 303-311.