Why did Brian get attacked by a porkupine in Hatchet?

Brian was attacked by a moose while trying to get a drink from the lake. He tried to run from the moose but the moose chased him and pinned him down. He was injured badly but recovered in a couple of days luckily. He was also sprayed by a skunk and hit with 8 quills by a porcupine. Hope I helped! :)

He was also "attacked" by a tornado and his shelter was destroyed so he had to start building it all over again.