It really depends on what you are interested in doing professionally. Both the domains, though data-driven, differ in terms of end applications. Big Data deals with enormous datasets while Data Science focuses on machine learning algorithms to build statistical models and drive insights from the chunk of Big Data.
Big Data is utilized by organizations to understand the market, improve efficiency, and drive competitiveness. Data Science, on the other hand, is involved with modeling techniques and methods to study the potential of Big Data. One can become a professional Data Scientist by enrolling in Intellipaat Data Scientist Course.
If you are expecting something that calls for the implementation of statistical and predictive analytics techniques, then Data Science is your calling. Data Science professionals use scientific methods, programming tools, and models to extract insights for better decision making.
Big Data is for those looking to work with diverse data types from various multiple sources and data processing. Big Data professionals typically work with Hadoop, Java, Hive, R, Tableau and create reports and dashboards.
Here is a video that draws a clear comparison to help you understand more about the difference between Data Science and Big Data.