Too Cold Outside? Try Out Polar Mammals’ Methods of Staying Warm

If temperatures in the teens (or the 50s for the warmer climates) make you grumble, be glad you’re not a mammal living in the Arctic or around Antarctica. These animals face much colder air temperatures of -40 to -76 degrees Fahrenheit. While humans bundle up with thick sweaters and jackets to get through the winter cold, mammals such as seals, penguins and polar bears stay warm with blubber, feathers and fur. How do these materials keep the arctic chill out?

Polar Bear

Credit: Getty Images

The ability of a material to insulate depends on how easily it lets heat pass through—a property called thermal conductivity. Fat has a low conductivity, which means it slows heat getting out and helps keep heat in. Marine mammals such as whales and seals have a layer of blubber beneath their skin. The blubber insulates their body so they don’t lose body heat while swimming in icy waters.

Feather and fur also have low thermal conductivity and are good for keeping warm. They also trap air—another substance with low thermal conductivity—creating an insulating layer of air around the body. If the animal feels cold, goose bumps fluff up their feathers or fur, which traps more air to slow down heat loss. This is why down jackets are so cozy: Down traps air, and this air layer insulates us.

You can test these materials out for yourself: This experiment in Advances in Physiological Education uses bubble wrap and vegetable shortening to demonstrate how fat and air work as insulators. Show us how your experiment turned out. Tweet a photo and use the hashtag #ISpyPhysiology.

Maggie KuoMaggie Kuo, PhD, is the former Communications and Social Media Coordinator for APS. Catch more of her writing in the Careers Section of Science Magazine.

Is It Cold in this Haunted House or Is It Me? Why You’ll Get Goosebumps This Halloween

Scary House on Top of the Hill

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Maybe it’s the chilly fall air. Or maybe it’s the macabre Halloween lawn decorations in your neighborhood. Both cool temperature and emotions can give you goosebumps. What causes goosebumps, and why can two different sources give you the same physiological reaction?

Goosebumps happen when tiny muscles at the base of each hair on your skin contract. This causes the hair to stand and the skin to buckle, making your skin look like a goose’s skin after its feathers have been plucked. The body releases the hormone adrenaline (also called epinephrine) when it feels cold, and adrenaline causes the skin muscles to contract. In animals, goosebumps fluff up the fur or feathers to trap in body heat. Humans, though, wear clothes and have a lot less hair, so this reaction doesn’t help much in keeping you warm.

Adrenaline is also released by fear or strong emotions, which is why you get goosebumps from watching a horror movie or thinking about an emotional event. In animals, this response makes their fur or quills stand up, helping the animal appear larger to scare off the attacker.

Adrenaline has a lot of other actions besides causing goosebumps. It’s a hormone released under stress, and it ramps up the body to deal with it. Other effects of adrenaline include sweaty palms, tears, trembling hands, a racing heartbeat and feeling “butterflies” in your stomach.

So this Halloween, whether it’s ghouls or just the crisp night air, know that goosebumps have you covered.

Maggie KuoMaggie Kuo, PhD, is the former Communications and Social Media Coordinator for APS. Catch more of her writing in the Careers Section of Science Magazine.

Tasting Food Literally: What Makes the Pumpkin Spice Latte Feel So Warming?

Pumpkin Spice Latte

Credit: Getty Images

Fall is around the corner, and coffee shops everywhere are rolling out their pumpkin spice-flavored warm drinks. The drink feels warm to the touch because of the temperature, but somehow the pumpkin spice flavor also tastes warm. Why do we associate warm or cold temperature with certain foods?

The body senses temperature through proteins on the nerves in the skin and tongue called transient receptor potential (TRP) channels. There are six TRP channels that respond to temperature, and each respond to different temperature ranges: painfully cold (TRPA1), cold (TRPM8), warm (TRPV4 and TRPV3) and painfully hot (TRPV1 and TRPV2).

Besides temperature, these proteins can also be stimulated by chemicals found in food. Chili peppers have capsaicin that stimulates TRPV1, the protein that responds to heat, which is why spicy foods feel hot even if the food itself isn’t piping hot. Mint contains menthol that stimulates TRPM8, the protein that responds to cold, which is why chewing mint gum feels refreshingly cool.

Pumpkin-themed drinks are usually spiced with cinnamon, cloves and nutmeg. These spices stimulate TRPV3, the protein that responds to warmth, making the pumpkin spice latte warm to the touch and taste. While you sip your spicy latte, explore other foods that stimulate TRP proteins in this Scientific American article.

Maggie KuoMaggie Kuo, PhD, is the former Communications and Social Media Coordinator for APS. Catch more of her writing in the Careers Section of Science Magazine.