Anusha Shankar

Rose Postdoctoral Fellow

I am curious about how animals manage their energetic needs under extreme circumstances.

For my Ph.D. I studied hummingbirds, the tiniest birds, in the cloud forests of Ecuador and the deserts of Arizona, to understand how they manage to stay alive on a daily basis. They spend energy incredibly quickly, and barely have any backup energy stores in the form of fat. They are therefore almost always a few hours from death. Their energy management strategy that most captured my attention was their use of daily torpor- an energy saving state similar to hibernation when they drastically lower their metabolic rate and their body temperature and save an average of 86% of energy every hour.

For my Rose Postdoctoral Fellowship, I will be investigating hummingbirds’ use of a shallow form of torpor. Mammals can drop their metabolic rate to varying extents—using torpor at various depths—but birds are not known to do the same. Over 40 species of birds are known to use some form of torpor, but each species is thought to have a minimum tolerable torpid body temperature that it will drop to, ambient temperatures permitting. Birds are not described to regulate their body temperature above that minimum in torpor, if ambient temperatures are close to or below their minimum body temperature. Hummingbirds have long been known to use deep torpor (dropping their core body temperature to between 6.5-20C). We discovered hummingbirds are also capable of regulating their body temperature at an intermediate state between that of sleep and deep torpor (surface temperatures ranged between 19.5–29C). The occurrence of shallow torpor in these birds clearly capable of lowering their body temperature further indicates that they are balancing the costs (e.g. sleep deprivation, loss of immune function, predation) and benefits (energy savings) of deep torpor.

I think that the existence of these variable torpid states in birds could help us better understand the physiological functions of sleep vs. torpor in birds, vs. mammals. Which physiological and cellular processes are deemed ‘essential’ in sleep vs. torpor?

I will employ a transcriptomics approach to answering this question with hummingbirds.

Education

Ph.D. Ecology & Evolution, Stony Brook University, New York
M.Sc. Ecology & Environmental Sciences, Pondicherry University, India
B.Sc. Advanced Zoology & Biotechnology, Stella Maris College, India

Outside the Lab

Beyond the Lab I am deeply invested in, and excited by, communicating my science to broad audiences of all ages. I have been working with National Geographic over the past few years to speak with classrooms, partner with educators to create science projects, give live science talks to adult and young audiences, and to create educational materials for schools. I have also given a TEDx talk in my hometown of Chennai, in India, written a children’s book, and published general science articles, such as in Current Conservation. I look forward to working with Cornell’s media lab to reach even wider audiences and incite a passion for science and a curiosity for the natural world everywhere I can. I also enjoy learning new languages, and love salsa dancing. LOVE it.

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