system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5- how do scientists know that a particular species' (panda, turtle, sharks, tigers) population is getting extinct?
gpt
They do studies to see how many of that animal there are in certain areas, and try to extrapolate outward from there. For example, if you know pandas can only live in bamboo forest, and you survey some random bamboo forest and find 1 panda per square mile, and you know there's only 100 square miles of bamboo forest left, you can make a guess that there probably aren't much more than 100 pandas.