October 29, 2008--Martian scallops don't suggest liquid water but may be evidence of subsurface ice in Utopia Planitia, a region of Mars's northern lowlands.

The sea creature-like shapes are actually large depressions likely caused when subsurface ice materials from an earlier era of high precipitation sublimated and turned directly into gas.

The erratic network of cracks, seen in this September 16 HiRISE image, resembles permafrost fractured by thermal contractions in Earth's cold climate regions.