Even robots like to have fun. NASA's rover on Mars showed off its playful side by snapping a picture of its own shadow. It's the latest self-portrait since the rover, named Opportunity, landed on the red planet in 2004.

The photo was taken in March and NASA released it this week. The solar-powered, six-wheel rover was at an outcrop on the rim of a massive crater. The late afternoon sun set the crater aglow and Opportunity waited for just the right lighting to send a postcard back to Earth.

The result was a dramatic view of Opportunity casting a shadow with the crater in the background.

After nearly five months in one spot, the tireless rover is rolling again to explore more rocks.

Its twin, Spirit, stopped communicating in 2010.