Unlike Dau Go cave, Bo Nau cave is not as deep and large. Looking out from the cave the visitor can enjoy the scenic beauty of Ha Long. The clear blue water with rocky formations rising forms a picturesque setting. Bo Nau is a compound word derived from two words, bo cau meaning pigeon and nau meaning brown. Bo Nau literally means brown pigeon. For some reason, many foreign translations refer to this cave as Pelican cave.
According to the fishermen in this region, long ago, when there were still few visitors, Bo Nau cave was home to thousands of pigeons. Today as more visitors and people begin to inhabit the surrounding islands, the pigeons have left until only the name Bo Nau remains out of habit of the local fishermen.