Morphometric evidence challenges delta interpretation of Jezero Crater’s channel network

River deltas along the shorelines of ancient Martian lakes and oceans are prime landing targets in the search for life, offering high potential for habitability and the preservation of biosignatures¹. NASA selected Jezero Crater as the landing site for Perseverance because its fan-shaped paleochannel network was identified as a delta2,3. Here we show that the Jezero Crater channel network is not consistent with a delta. Instead, its topology exhibits statistical similarities with a fluvial fan – another landform with channel networks that may be less promising for detecting past life. We quantify the Jezero channel network morphometrics, and contrast with the Eberswalde network, that is consistent with a delta. Our results emphasize the need for rigorous quantitative analyses in identifying landforms on Mars and other planetary bodies. Our findings provide new insights into the processes shaping channel network topology on Earth and Mars.