As humans, we have left more than a carbon footprint over the past centuries. But what is the goal of the lower animals since that is the problem? What is the limit when there are no factual limits? There are so many questions, but few answers. Many philosophers and environmentalists argue various points regarding the humanity of animals. Additionally, endangered, threatened, and extinct species bring an additional argument as to whether endangered species are worth fighting for. 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 of these species. that they found. Since then, the species have become extinct again. Critics criticize the recurring argument that the ESA is a sufficient organization to preserve the lives of these endangered or threatened species. Studies show that between 2006 and 2011, the ESA managed to keep an average of 415 species in the threatened category. Over a ten-year period, the ESA spent $508,704,000 on endangered species preservation alone. Therefore, the cost that Waterfrank entailed is actually a significant dent in our wallets, and yet the results look bleak. Or should we settle for the numbers in Table 1. The ESA faces various obstacles that have exhausted the list of species types in the first table. Variables include, but are not limited to, habitat destruction, overexploitation, and the introduction of exotic species. In July 2006, a federal judge halted a $320,000,000 irrigation project over fears it would disrupt 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 believed the species...... middle of paper ......r Bighorn Sheep. ". Big Horn Institution, nd Web. November 29, 2011. Rolston, III, Holmes. “Environmental ethics: values ​​and duties towards the natural world”. The broken circle: ecology, economics, 1991. Web.: Duties towards sentient life Philadelphia: Temple University, 1988. eBook..