We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is Bergmann's Rule?

Mary McMahon
By
Updated Jun 04, 2024
Our promise to you
All Things Nature is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All Things Nature, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Bergmann's Rule is a theory which states that animals will tend to be larger at higher latitudes than they will be at the equator, correlating average temperatures with body size. This principle is one among a family of “ecogeographic rules,” theories posited by biologists to explain natural phenomena on the basis of ecology and geographic location. This rule is not without controversy, not least because there are some notable exceptions which would seem to disprove the rule, such as the admittedly massive African elephant.

The idea behind Bergmann's Rule is that the lower the ratio of body mass to surface area, and less heat loss an animal will experience. The larger the ratio, the more heat loss will be experienced. In regions like the Arctic, animals naturally want to reduce the amount of heat they lose, so that they do not become hypothermic and die. In equatorial regions, on the other hand, animals want to lose heat, so that they do not turn hyperthermic and suffer the related health complications.

According to Bergmann's Rule, populations of the same species of animal should appear in different sizes, depending on their latitude, and closely-related species should also demonstrate size variance which can be correlated with their natural habitat. And, as a general rule, equatorial animals are supposed to be smaller, while Arctic animals should be correspondingly larger.

There is some evidence to support Bergmann's Rule: polar bears, for example, are much larger than spectacled bears, which live closer to the equator, and a number of animals do develop size variation both within species and in closely related species which can be correlated to geographic location. This theory has also been used to explain the typically heavier body types of people from Arctic regions when compared to equatorial peoples.

However, a number of counterpoints to Bergmann's Rule can also be pointed out. Some Polynesian peoples, for example, have famously heavy body structures and a tendency to grow overweight with age, despite the fact that they live in warm climates, and some Arctic animals are quite small, while some equatorial creatures get very large. In all probability, Bergmann's Rule is only one among a large family of factors which can influence the size and development of creatures on Earth, and while it is something to be considered, it is not a hard and fast explanation for the wide variance of body types, shapes, and sizes on the Earth.

All Things Nature is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Mary McMahon
By Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All Things Nature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Discussion Comments
By anon939712 — On Mar 15, 2014

Are there any other examples of animals that follow the rule?

By B707 — On Jun 20, 2011

Bergman's Rule sounds like just a theoretical idea. There are way too many exceptions to call it anything else. I think that perhaps the variation in size and shape of animals has to do with the migration and adaptation of species.

Also their diets and how much food was available at various times in their history may have more to do with variable size. The temperature and latitude might have something to do with the size of animals, but certainly not a big part in it.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a...

Learn more
All Things Nature, in your inbox

Our latest articles, guides, and more, delivered daily.

All Things Nature, in your inbox

Our latest articles, guides, and more, delivered daily.