giant Pacific octopus that attacked a remotely operated submarine off north Vancouver Island could have been senile or maybe just peckish, a marine biologist said Wednesday. "Large male octopuses in the last part of their lives become senescent, or senile," said Jim Cosgrove of the Royal B.C. Museum. "They get to be like humans, doddering old fools that have inappropriate behaviours such as being out in the daytime," said Cosgrove, an expert in octopus behaviour.