Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

Hibernation and Hypoxia

Extreme Physiology of Diving

Can you imagine what would happen to your body if you dove up to 1700 meters deep in the ocean for an hour and a half, or experienced months of food deprivation? In the case of deep diving, the high pressure causes the collapse of the lungs of terrestrial mammals (including humans!) and depletion of body oxygen stores, whereas long fasting periods compromise health and induce muscle wasting. Northern elephant […]

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Experimental Biology 2021: Q&A with Dr. Michael Tift and Anna Pearson

We are delighted to speak with Anna Pearson (MS student) and her mentor Dr. Michael Tift, Assistant Professor at the University of North Carolina – Wilmington. Anna presented her research “First report of red blood cell lifespan in a marine mammal: An insight into endogenous carbon monoxide (CO) production” at the 2021 Experimental Biology conference last month. What made you interested in studying red blood cells in dolphins?Dr. Tift became interested […]

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Experimental Biology 2021: Q&A with Molly Simonis

We are delighted to speak with Molly Simonis who is currently a PhD Candidate working with Dr. Lynn Hartzler at Wright State University. Molly is a member of the Comparative and Evolutionary Physiology section of the American Physiological Society and she presented her research “Captive Big Brown Bats (Eptesicus fuscus) Display Hypothermia and Hypometabolism” at the 2021 Experimental Biology conference last month. Q: What made you interested in studying big brown […]

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2021 August Krogh Distinguished Lectureship

The August Krogh Distinguished Lectureship is the highest award given by the Comparative and Evolutionary Physiology section of the American Physiological Society. As the name implies, it is awarded to a distinguished physiologist who has made major and meritorious contributions to the field. This year’s August Krogh Distinguished Lecture was awarded to Dr. Ken Olson, Emeritus Professor, Indiana University School of Medicine – South Bend. His talk at the Experimental […]

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Surviving the cold

The ability to regulate body temperature is critical for animals. This is especially true for small mammals as they have a larger surface area resulting in more heat loss to the environment than larger animals. Animals that stay active during the winter likewise have to spend more energy to stay warm. To do this well, they need to balance heat loss with heat generation through shivering as well as non-shivering […]

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Extreme tolerance of dehydration stress

Talk about an extreme animal. During the rainy season annual killifish, Austrofundulus limnaeus, lay eggs that are resistant to droughts. This is an important attribute for a fish that lives in temporary pools of water. The stress-resistant embryos within the eggs literally shut down their metabolism to survive months – possibly years without water. For many fish, exposure to air (and oxygen) can cause profound oxidative stress. Remarkably, this is […]

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Anoxia tolerance in goldfish

The reason mammals are not very good at tolerating hypoxic (i.e. low oxygen) environments, is because the brain relies heavily on oxygen for metabolism. It is so stingy, it uses about 20% of the oxygen in the body to make ATP. Without oxygen, the brain has to rely on glycolysis to make ATP and this process is not good at meeting the energy requirements of the neurons, ultimately resulting in […]

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Even the brainless need sleep

Most animals that we know of sleep. Sleep is very important for a healthy brain and our brains are important in regulating sleep. Interestingly, recent studies have shown that the cerebrospinal fluid actually washes out toxins from the brain when we get enough sleep at night. That “rinse cycle” so to speak is the brain’s way of staying healthy and is thought to prevent neurodegenerative diseases like Alzheimer’s. You may […]

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Extreme Fasting

While giant pandas roll in horse manure to stay warm in the winter (that’s a different story), other animals spend up to 8 months hibernating to conserve energy during times of reduced food availability and freezing temperatures. During their long winter’s nap, animals such as the Arctic ground squirrel and 13-lined ground squirrel go without food or water while at the same time avoiding muscle wasting – a rather impressive […]

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How a really long winter’s nap can impact sperm production

As winter approaches, hibernating animals will finalize their preparations for taking a ‘long winter’s nap’. These remarkable animals reduce their metabolism to help conserve energy at a time when environmental resources are scarce and considerable energy would otherwise need to be spent on just staying warm. For many species of hibernators, periodically entering this state of torpor allows them to reduce their energy needs by 90% compared to intermittent states […]

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