Life Lines by Dr. Dolittle

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Tag Archive for ‘metabolism’

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Now we know how life underground reduces metabolism

…at least for mole-rats. African mole-rats live in dark underground dwellings where oxygen and food are scarce, and humidity and temperatures are high. These animals have low metabolic rates and body temperatures uniquely adapted to their life underground. Metabolism is controlled in part by thyroid hormones. To understand the role of thyroid hormone in mole-rats, researchers examined the thyroid gland and hormones in naked mole-rats (Heterocephalus glaber) as well as […]

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Migratory birds create their own water to prevent dehydration

Migratory birds are amazingly adapted for long-distance flights and can switch the fuels they rely on to support their endurance activities. Unlike humans that burn mainly carbohydrates for endurance exercise, avian flight is fueled mainly by fats and some proteins. In a recent study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology researchers examined how white-throated sparrows (Zonotrichia albicollis) prepared for migration. By altering the […]

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Birds may stay warm with the help of red blood cells

Researchers at Lund University in Sweden were interested in understanding how birds adapted to cold weather. Birds can’t turn up the heat in their birdhouse, so it is important for them to find physiological ways to stay warm. While they can store body fat and grow more feathers for insulation, metabolism is the primary way endothermic animals create body heat. Mitochondria produce cellular energy (ATP) but can also create heat […]

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Tenrecs may shed light on the evolution of body temperature regulation

The common tenrec (Tenrec ecaudatus) just may be a living representative of ancestral placental mammals and they are very interesting when it comes to body temperature regulation and torpor. Torpor is a complex series of physiological changes that reduce an animal’s physical activity as well as heart, breathing and metabolic rates, which also results in decreases in body temperature than can be as low as their surrounding environment. Many mammalian […]

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Oddity of mammalian red blood cells

Mammalian red blood cells do not have a nucleus, which is different from birds, amphibians, reptiles, and fish (see image above). Many textbooks report that the absence of a nucleus provides room for more hemoglobin within the cells, which is important to fuel the relatively high metabolic rates of mammals. Hemoglobin is an important oxygen-binding molecule that allows the red blood cells to transport oxygen to tissues throughout the body […]

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Why shrews don’t need sweaters

Research presented by Dr. Tobias Fromme (Technical University of Munich) and colleagues at the 2021 Experimental Biology conference shows that Etruscan shrews (pictured above) have a rather large amount of fat located between their kidneys, which is close to their major blood vessels. This fat depot is a mixture of both brown and beige adipose tissue and is thought to help generate metabolic heat to keep these tiny mammals warm […]

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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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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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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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Live fast, die young

Researchers have long known that smaller animals have higher metabolisms and tend to die younger than larger animals. Think about it – a mouse typically only lives about 2 years whereas an elephant in the wild may live 50-70 years, depending on the species. After studying over 700 species of birds and 540 species of mammals, scientists discovered that migratory animals also live faster (mature and reproduce earlier) and die […]

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