The Zoological Survey of India (ZSI), established in 1916, is the national organisation for animal taxonomy and biodiversity conservation under the Ministry of Environment, Forest and Climate Change. ZSI scientists explore, survey, and document India's faunal diversity across its 16 biogeographic zones—from Himalayan alpine meadows to tropical rain forests, marine coasts, and desert ecosystems. India harbours approximately 1,02,000 known animal species, and ZSI scientists work on species discovery, taxonomic descriptions, population assessments, and conservation biology studies that feed into protected area management and IUCN red-listing.

The ZSI Scientific Officer exam (100 MCQs, 120 minutes, -0.33 negative marking) covers Zoology (Animal Morphology, Physiology, Cell Biology, Genetics, Embryology), Animal Taxonomy and Systematics (invertebrate and vertebrate groups, ICZoN nomenclature, phylogenetics), and Ecology & Conservation Biology (biogeography, population ecology, wildlife laws, conservation genetics). Senior positions tested through UPSC require descriptive writing, species identification from morphological keys, and knowledge of current biodiversity policy.

ZSI scientists can specialise in Vertebrate Zoology (mammals, birds, reptiles, amphibians, fishes), Invertebrate Zoology (insects, molluscs, arachnids, marine invertebrates), Marine Biology, Animal Genetics and Molecular Systematics, or Entomology. The ZSI maintains national zoological repositories at its headquarters in Kolkata and regional stations in Pune, Chennai, Jabalpur, Dehradun, Shillong, and Port Blair. Collaborative work with WWF, WII (Wildlife Institute of India), and international natural history museums provides rich research opportunities.

While ZSI focuses on animal diversity and faunal taxonomy, BSI covers plant diversity and botanical taxonomy—both are under MoEFCC and follow similar career structures. ZSI posts tend to involve more field work in wildlife sanctuaries and national parks, whereas BSI work often involves herbarium documentation and floristic surveys. Both require strong taxonomic knowledge and field identification skills. Candidates with an interest in wildlife ecology and animal conservation are better suited for ZSI, while botanists and plant scientists align more with BSI.

Study Hickman et al. for invertebrate zoology, Kotpal's series for Indian fauna, and Strickberger for genetics. Cover systematics and phylogenetics from Wiley's Systematics. For ecology and conservation, study Odum's Fundamentals of Ecology, Singh's Plant Ecology, and India-specific wildlife status reports from WII and MoEFCC. Study the Wildlife Protection Act 1972, Biological Diversity Act 2002, and CITES schedules thoroughly. CSIR-NET Life Sciences papers are excellent practice material. Field identification skills, particularly for common Indian bird, reptile, and mammal groups, are highly valued.