The large island that is part of Indonesia and known for its biodiversity is Borneo. Borneo is covered by ancient rainforests, which are home to a remarkable variety of wildlife, including iconic species like the orangutan and Borneo pygmy elephant. The island is shared by three countries: Indonesia, Malaysia, and Brunei. Borneo's ecosystems are crucial for global biodiversity and are currently facing challenges due to logging, mining, and land conversion for agriculture.