Caterpillars? They are unobtrusive creatures. Yet they play a big role in people’s daily lives. A gutter brush is sometimes called a gutter caterpillar. Just like caterpillars, a Gutter-Brush takes away a lot of vegetative material, like leaves, pine needles, pieces of straw, etc. This is how the caterpillar keeps is hiding spot safe. Ecologically speaking, both caterpillars and gutter caterpillars make a contribution. The physical resemblance between a caterpillar & a gutter brush? That’s obvious. The characteristic spines of the gutter caterpillar or Gutter-Brush create a barrier from leaves, nests and excess debris.