Endangered species can be defined as a group of animals or plants in danger of becoming extinct. This book presents an overview of such species as a result of certain factors such as climate change, extensive urbanisation, overgrazing, and agricultural expansion. The first chapter of this book describes China's attempt to protect its rare, threatened, and endangered species in their natural habitats. It identifies the root causes of species loss as well as China's participation in international environmental conventions and its participation in non-governmental organisations (NGO's). Chapter Two reviews the ways in which the abundance of endangered marine benthic species are estimated using distance sampling through SCUBA diving. Distance sampling is a widely used set of methods for estimating abundance and/or density of biological populations. It is a standard method for abundance estimations for many endangered species. Chapter Three reviews the causes of medicinal species endangerment in the Middle East as well as conservations measures that are being used to protect and preserve them from extinction. Chapter 4 describes a species known as Pine marten (or Martes martes), which is an animal in the weasel family. This chapter reviews the reasons why this species is in danger of extinction (such as the presence of incidental killings, forest reduction, and habitat fragmentation in recent years) as well as the measures that have to be taken to prevent a further decline in population. The northern pike, one of the most important freshwater fish, might become an endangered species due to its rapid decline in population from overfishing, habitat reduction, and climate changes. Chapter Five addresses these problems as well as explores the actual conservation and management state of this species in Europe, comparing genetic and molecular ecology data obtained for European and North American populations. Chapter Six is a description of a case study of the river otter, Lontra longicaudis annectens, present in Central Mexico, and the ways in which ecological niche modelling and place prioritisation procedures were used to identify areas for conservation and restoration for this species. Chapter Seven describes the impact that deforestation has on biodiversity conservation in Mexico by measuring its effects on mammal species' distributions, delineation of biogeographical regionalisation, the effectiveness of conservation area networks and area prioritisation for biodiversity conservation. Finally, the last chapter of this book presents an overview of the global usage of felines in traditional folk medicine and as a result, their danger of becoming extinct.