4 Animal Comparisons We Use Incorrectly

What does it mean to sweat like a pig? How cute is a bug's ear? Here are four animal comparisons we make all the time that don't actually mean what they think they mean.

Sabrina Stierwalt, PhD
3-minute read
Episode #157

Do these hot summer days leave you sweating like a pig? Are you so busy running around that you’re eating like a bird? Many of the similes we use that rely on comparisons to the animal kingdom don’t make scientific sense. Here are four animal comparisons that don’t actually mean what we think they mean.

Sweat Like a Pig

When temperatures are high, we humans produce sweat to keep cool. We have between 2-4 million sweat glands covering our bodies. Women tend to have more, but less active, sweat glands than men. When we sweat, our skin feels cooler thanks to the moisture. That sweat then evaporates, taking energy in the form of our body heat with it.

While pigs do have a few sweat glands, they are not useful for temperature control like ours so they get an unfair rap as profuse sweaters. To keep cool, pigs instead roll around in mud to get the same evaporation effect as sweat. So next time you’re ranting about the summer heat, perhaps you should say you are sweating like a hippo.

Eat Like a Bird

Quite often my toddler gets accused of eating like a bird which is meant to say that she eats very little in both quantity and variety. However, birds actually eat a wide variety of nectars, seeds, and insects. They also eat a lot of them to maintain their fast metabolisms and high body temperatures. Birds often help plant life thrive by eating so many of the insects that would otherwise consume the plants.

How much a bird eats depends on the bird’s size and activity levels as well as the temperature outside. Bigger birds have to eat less relative to their body weight—somewhere around a quarter—than smaller birds that can eat close to half of their body weight every day. On colder days, birds will eat even more to stay warm.

A chickadee eats somewhere around 35% of its weight daily, while Canada geese consume about 10% of their weight in grass.  Hummingbirds can consume over twice their body weight every day, including their weight in nectar and thousands of insects!

So be careful next time you tell someone they eat like a bird, since you are actually telling them they eat quite a lot! As far as my toddler is concerned, I actually think she eats more like a python—nothing for days and then boom! A huge meal.


Please note that archive episodes of this podcast may include references to Ask Science. Rights of Albert Einstein are used with permission of The Hebrew University of Jerusalem. Represented exclusively by Greenlight.

About the Author

Sabrina Stierwalt, PhD

Dr Sabrina Stierwalt earned a Ph.D. in Astronomy & Astrophysics from Cornell University and is now a Professor of Physics at Occidental College.

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