For its novel way of maintaining boundaries, consider Octopus tetricus, also known as the gloomy octopus and the common Sydney octopus. If another creature gets too close, it may respond by throwing things, according to a study published recently in the journal PLOS One. The cephalopods, native to seas off New Zealand and eastern Australia, were caught on camera throwing shells, silt, and algae, which sometimes hit animals that came too near their dens. The recipients included various fish, other gloomy octopuses—and even the underwater cameras. This is the first time a throwing behavior has been reported among octopuses. Though scientists aren’t certain of the motivation, it may have something to do with “the octopus equivalent of personal space,” says the study’s lead author, Peter Godfrey-Smith, a professor at the…