Robotium is an extension of the Android testing framework, designed specifically for mobile app testing, offering full support for native and hybrid Android apps. It provides a higher level of abstraction than Selendroid, recognizing UI elements by their internal application IDs, making test cases more robust and readable. Robotium also offers better support for activities, gestures, device manipulation, and Android IDE integration, making it a natural choice for developers with a background in native Android development. In contrast, Selendroid is based on Selenium, a framework designed for web browser testing, requiring adaptations to enable mobile testing using a Selenium-based framework. While both frameworks have their strengths, the choice between Robotium and Selendroid ultimately depends on the tester's skill set and experience.