There are several research papers and journals that can be referred to for the Zoology optional subject in the UPSC exam. These resources provide valuable information and insights into various topics related to zoology. Here are some of the notable research papers and journals that you can consider:

1. Journal of Zoology:
- This is a renowned scientific journal that covers a wide range of topics in zoology. It publishes original research articles, reviews, and commentaries on various aspects of animal biology.
- The Journal of Zoology covers diverse areas such as animal behavior, ecology, physiology, genetics, and evolutionary biology. It is a valuable resource for understanding the latest developments in the field of zoology.

2. The American Naturalist:
- This interdisciplinary journal publishes research articles in the field of biology, including zoology. It focuses on evolutionary biology, ecology, and population biology.
- The American Naturalist features studies on animal behavior, adaptation, conservation, and biodiversity. It is a highly respected journal that publishes high-quality research articles.

3. Proceedings of the Royal Society B: Biological Sciences:
- This scientific journal publishes research articles in various fields, including zoology. It covers a wide range of topics such as animal behavior, ecology, evolution, and physiology.
- Proceedings of the Royal Society B publishes original research papers, reviews, and perspectives that contribute to the understanding of biological sciences.

4. Journal of Experimental Zoology:
- This journal publishes original research articles, reviews, and perspectives in the field of zoology. It covers various areas such as animal physiology, developmental biology, and comparative biology.
- The Journal of Experimental Zoology is a valuable resource for understanding the mechanisms behind animal behavior, reproduction, and development.

5. Animal Behaviour:
- This journal focuses on the study of animal behavior and publishes research articles that investigate various aspects of animal behavior, including social behavior, communication, and cognition.
- Animal Behaviour features studies on a wide range of animal species and provides insights into the evolutionary basis of behavior.

These research papers and journals can serve as excellent resources for your preparation for the Zoology optional subject in the UPSC exam. They provide up-to-date information, in-depth analysis, and critical perspectives on various topics in zoology.