Endangered species are organisms that are close to becoming extinct, which means there will be no more of them left on Earth. This can happen for many reasons. For example, some animals are hunted too much by humans, so their population decreases a lot. Other species lose their habitats, which are their natural homes, because of deforestation or pollution. When a species becomes extinct, it means there are no living individuals of that species left. It’s a sad thing because it means that the unique characteristics of that species are lost forever.