AI systems are no longer just specialized research tools, but everyday academic companions. A large-scale study analyzed one million anonymized student conversations on Claude.ai to understand how students naturally integrate AI into their academic work in real settings. The key findings include that STEM students, particularly Computer Science students, show higher adoption rates of AI tools like Claude, while Business, Health, and Humanities students exhibit lower adoption rates. Students primarily use AI systems for creating and analyzing content, such as coding projects or explaining complex concepts. However, there are concerns about students outsourcing cognitive abilities to AI systems, stifling the development of foundational skills needed to support higher-order thinking. The study highlights the need for educators to redefine assessment and cheating policies in an AI-enabled world.