As humans we have left more than one carbon footprint over the last few centuries. But what is the purpose of the lower animals since this is the issue at hand? What is the limit when there are no factual limitations? There are so many questions, but still few answers. Many philosophers and environmentalists argue various points regarding the humanity of animals. Furthermore, endangered, threatened and extinct species further reinforce the question of whether fighting endangered species is worth it. How much does it cost? In 1973, the Endangered Species Act (ESA) was created to conserve threatened and endangered plants and animals and the habitats in which they were found. Since then the species have been further depleted. Critics debate whether the ESA is a sufficient organization to preserve the lives of these endangered or threatened species. Studies show that over the period 2006-2011 the ESA was able to maintain an average of 415 species in the endangered species category. Over the course of ten years, ESA spent $508,704,000 solely on the conservation of endangered species. Therefore, the cost that Waterfrank intended to imply is actually a big dent in our wallets, and yet the results appear to be bleak. Or we should settle for the numbers on table one. The ESA has an ongoing battle with various obstacles that have exhausted the list of species types in table one. Variables include, but are not limited to, habitat destruction, overexploitation, and the introduction of exotic species. In July 2006 a federal judge blocked a $320,000,000 irrigation project over concerns that it would disturb the habitat of a woodpecker that may or may not be extinct. The dispute concerns the ivory-billed woodpecker. The last confirmed sighting of the bird in North America was in 1944, and scientists had thought that the spe...... middle of paper ......r Bighorn Sheep. ". Big Horn Institution, n.d. Web. November 29, 2011. Rolston, III, Holmes. "Environmental Ethics: Values ​​and Duties to the Natural World." : Duties to Sentient Life Philadelphia: Temple University, 1988. eBook.