Dani Crain spends most of her time cutting apart layers in whale earwax.
Yes, whales have ears! But unlike you and me, they can’t clean their ears. So earwax builds up in their ear canals over their entire lives, forming layers like tree rings. I use this plug of earwax, or earplug, to investigate the long-term trends in stress and sex hormones in baleen whales.
I like to joke that I am an “Endochronologist,” because I am broadly interested in using using animal tissues that grow over time to track how the environment impacts trends in stress, reproduction, diet, and location. The biomarkers I use to investigate this are hormones and nitrogen/carbon stable isotopes.
I’m currently looking for a postdoctoral position, please contact me if you’d like to chat!
In my off time, I enjoy powerlifting, knitting, podcasting, reading science-fiction/fantasy, baking, and cooking.
I am currently a 5th year in the Laboratory of Ecological and Adaptational Physiology (LEAP) at the Biology Department of Baylor University. I am investigating the long-term trends in stress and sex hormones in baleen whales using their waxy earplugs. Moreover, I aim to make STEM graduate school and careers more inclusive (see Other Projects).
I am broadly interested in using animal’s hormones to help us learn more about their environment.
Honors & Awards:
PhD Candidate in Biology, 2020
M.E.M. in Coastal Environmental Management, 2012
B.Sc. in Ecology & Evolution, 2009
University of California, Santa Cruz
Under the guidance of Dr. Stephen Trumble and in collaboration with Dr. Sascha Usenko, I reconstruct baleen whale lifetimes using the hormones in their earwax. Whales produce earwax which builds up in their ear canals over time. This earwax forms a plug that, when cut in half, shows layers similar to tree growth rings (above). Each of these layers correspond to 6 months of time and begin forming in utero until death. This means we can assign a specific age and year to each layer in the earplug. We use the hormones from these layers to show when an individual whale experiences stress, when they reach sexual maturity, and when they are pregnant. Big picture this allows us to look at the environment at the time these animals were alive. To date, we have 150 years of data from the mid-1800s to present day from more than 40 individual baleen whales, including blue, fin, humpback, gray, and minke whales.
The ability for researchers to extract hormones and contaminants from baleen whale earplugs is still very new. Some of the basic questions, like how hormones in the earplugs vary in different tissues is still unknown. Furthermore, much of the known life history for these animals is from long-term observational datasets, which can be subject to sampling biases. Earplugs do not have these same limitations.
Therefore, the focus for my PhD is: 1) assessing steroid hormone concentrations in the earplug, baleen, and blubber of the same individual baleen whales, 2) determining how three stress biomarkers vary in the same layers of an earplug of baleen whales, and 3) analyzing progesterone concentration in earplug layers to determine how many pregnancies a whale experiences in her lifetime.
Research Covered in the News:
- The Atlantic: “The History of the Oceans Is Locked in Whale Earwax”
- National Geographic: “Earwax reveals how humans have changed whales’ lives”
- Baylor University: “Baylor Professors Use Whale Earwax to Reconstruct Whale Stress Levels Spanning More Than a Century”
- Natural History Museum - London: “Whale earwax reveals just how much human activity can stress out marine mammals”
- Natural History Museum - London Video: What can we learn from whales’ earplugs?
- ARS Technica: “Whales are stressed out by climate change, and it shows in their earwax”
- Smithsonian Magazine: “We Know How Stressed Whales Are Because Scientists Looked At Their Earwax”
In 2013 my adviser, Dr. Stephen Trumble, in collaboration with Dr. Sascha Usenko at Baylor University, published the first paper looking at hormones and contaminants in whale earplugs. Since then, our labs have made connections with museums and stranding networks world-wide to access hundreds of earplugs. Farzaneh Mansouri and Zach Winfield, both PhD candidates in Dr. Usenko’s laboratory, and myself have spent many months of our lives cutting the earplug layers apart, extracting stress and sex hormones, and running ELISAs to determine hormone concentrations in the layers. My PhD chapters and papers are based off this work.
Progesterone, the pregnancy hormone, plays a huge role in population dynamics when extracted from earplugs.
There are three stress biomarkers that the marine mammal field is interested in right now: cortisol, corticosterone, and aldosterone.
I examine stress and sex hormones in the earplug, baleen, and blubber of the same individuals to ascertain the consistency of hormone deposition.
Before starting my PhD in Biology at Baylor University in August 2015, I was an adjunct professor at Cosumnes River College, where I taught Anatomy & Physiology and Foundations of Biology, and California State University Sacramento, where I taught Human Reproductive Physiology.
Currently, I am a teacher of record and have taught lab courses for anatomy & physiology for nursing track students as well as introductory biology at Baylor University. In Spring 2017 I won the Outstanding Graduate Student Instructor Award while teaching Bio 2401, Anatomy & Physiology.
From left to right: Biology Department Graduate Program Director Dr. Ryan King, Acting Vice Provost for Administration Dr. Gary Mortenson, myself (Dani Crain), and Vice Provost and Dean of Baylor Graduate School Dr. J. Larry Lyons after the award ceremony.
“Science benefits from diversity.” In this vein, I have co-founded Present Your PhD (PyPhD) and acted as co-organizer for Women in Science and Engineering (WISE) at Baylor University from 2017-2019. Furthermore, seeing as how life as a graduate student can be isolating and stressful, I co-founded the CMHD/EEO Graduate Student Society (CEGSS) in 2017 within the Biology Department at Baylor University to make support structures available to graduate students, as well as increase camaraderie. Finally, I co-founded a podcast with fellow graduate students: STEMculture Podcast, where we focus on demystifying aspects of graduate school and STEM culture.
STEMculture Podcast is a podcast focused on improving the culture of STEM by talking about topics that affect graduate students, postdocs, early career researchers and more.
Graduate students need more development of skills and techniques to be successful in their masters or PhD. Here, I share the techniques and skills that have worked for me.
A graduate student society to increase camaraderie among graduate students of the Biology Department of Baylor University for the two tracks: cellular, molecular, health & disease/ecology, evolution, & organismal biology.
Women in Science and Engineering (WISE) at Baylor Univerity: We aim to support each other, make STEM more inclusive, and mentor new faculty.