the cave leeches expressed friendship/ 洞穴水蛭竟然对我表现友好

We have been exploring this cave complex for more than two years. This video introduces a little-documented species of cave leech. They don't suck blood like normal leeches.
两年多来，我们一直在探索这个洞穴群。 该视频介绍了一种鲜为人知的洞穴水蛭。 它们不像普通水蛭那样吸血。