According to the man, why did the bear attack him and his friends?

W: Hi, Dick. How’s the camping last week?
M: Oh, it was horrible. We nearly got killed.
W: What happened?
M: Well, when we were walking on the path along one of the hills a bear suddenly jumped out of a bush and started to chase us.
W: That’s terrible. Did anybody get hurt?
M: Fortunately, we ran away before the bear got closer. We all agreed that we had never run so fast in our entire lives.
W: So why did the bear try to attack you? Was it hungry and looking for food?
M: No, it was more horrible. We later found out that the bear was a mother. And she was separated by us from her child. She jumped out because she feared that her kid would get hurt. After the camping we’ve learned not to get between an adult bear and any young bears.
W: But how could you make sure that you can see the bears, if both the mother and the children are hidden in a bush?
M: Well, [2B] it’s actually easy to avoid meeting bears, because they are shy animals and normally avoid human beings. In most of the cases they attack because they are shocked by the unexpected presence of human. What you have to do is to scare them away by making noises, before you get too close.
W: I see, so next time when I go camping I’ll sing aloud when I’m walking.
M: That’s a good idea.