The Department of Natural Sciences was started in 1948. A full-fledged Department of Zoology was started in 1957 offering B.Sc Zoology. In spite of being an undergraduate department, it was recognized officially as a Center for Research by the university of Madras in 1965. In 1985 the department was upgraded into a postgraduate department and started offering M.Sc Zoology with emphasis on environmental biology. A postgraduate diploma course on Medical Lab Technology was introduced in 1988. The sequential M. Phil program in Zoology of the University of Madras for the experienced college teachers was conducted in the department and subsequently permission was granted for full time M.Phil course in 1988. In 2003, the department started M.Sc. in Medical Lab Technology and in 2004 the department started M. Sc in Biomedical Instrumentation Science. In the academic year 2005-06 the University of Madras granted affiliation for B. Sc Advanced Zoology and Biotechnology. This curriculum replaced B. Sc Zoology. It is the only department to offer three post graduate programmes.
The department has many FIRST to its credit
1. The very first research publication of Loyola College is from this department in the year 1949
2. In spite of being an undergraduate department in 1965 it was recognized officially as a center for research by the University of Madras for the purpose of research guidance for M.Sc by research as well as Ph.D
3. It is the only department to produce successfully more than 100 Ph.Ds
4. It is the first to offer M.Sc in Medical Laboratory Technology in an arts and science college
5. It is the first to offer M.Sc in Biomedical Instrumentation science under the innovative courses of UGC in an arts and science college