Preheat the oven to 375°. Unroll crescent dough; separate into 8 triangles. Cut each triangle in half lengthwise, forming 2 triangles. Spread 1/2 teaspoon pesto over each triangle; place 1 rounded teaspoon of crab along the wide end of each triangle.
Roll up triangles from the wide ends and place point side down 1 in. apart on an ungreased baking sheet.
Bake until golden brown, about 10-12 minutes. Serve warm.