Talk:Bergmann's rule

Recent evidence

I have found a BBC article pointing to shrinking birds related to global warming, thus confirming Bergmann's rule. Could someone please update this article. Link: http://news.bbc.co.uk/earth/hi/earth_news/newsid_8560000/8560694.stm Charea (talk) 01:32, 14 March 2010 (UTC)

Factual "Accuracy"

It is FINE to put a "Factual accuracy Poster" on an Article: BUT it is misleading to the Article, or to the intent of "Bergmann's Rule"/Bergmann's Law.....This is a law based on observation, as well as statistical verification in various species-(i.e. by examples on different continents, different ecosystems): It is also claimed that for humans: Bergmann's Rule explains why humans living in the Arctic have to be shorter, stouter, and rounder. A sonoran-desert guy, trying to live taller, skinnier in the Heat.... -Mmcannis (talk) 15:39, 9 December 2007 (UTC)

inconsistencies in assertions and logic

There's a failure in the logical thread of this article that ought to be cleaned up. I don't know if it's a failure of the theory, or of the description. If it's the former, it should be explained as such. If it's the latter, the theory needs to be described better.

I'd like to see citations matched to assertions in this article. Or a rewrite by an author with some authority on the topic. As it is now, the logic of the theory doesn't carry through in all examples given.

"...the body mass increases with latitude and colder climate." That's the meat of the matter.

"For example, northern Asians are on average larger than their Southeast Asian counterparts." That follows the logic.

"Southern Europeans, such as Italians, tend to be shorter on average than Northern Europeans, such as Swedes, which contradicts Bergmann's rule..." That on the other hand, doesn't. All other things being equal (e.g., girth, density), taller equates to more mass. It doesn't state that Italians are butterballs or that Swedes are beanpoles, and even then this doesn't directly address mass, but area/mass.

"...(taller frames yield a higher surface area-to-mass ratio, which would be expected to occur with greater frequency in warmer climates according to Bergmann's rule)." But the theory in the first paragraph mentions NOTHING about area-to-mass ratio! It simply states MASS.

Simply put, the area-to-mass ratio makes a lot of common sense, but it's not the definition of the theory this article describes.

--Erielhonan 05:55, 24 March 2006 (UTC)

Sa/Vol ratio corresponding to an increase in mass/volume.

I think the main problem that Erielhonan encounters is that the article doesn't mention the intrinsic relationship between increased volume and a decreased surface area to volume ratio (Sa/Vol). The article somewhat mistakenly uses the term 'mass', when it is in fact 'volume' that is important (even though, with animals, one could argue that an increase in mass accompanies an increase in volume, physically speaking, this isn't always true). The example that I find most useful is that of a simple sphere. In calculating the volume of a sphere, one must cube the radius, but the surface area uses the square. Thus, a larger sphere will mathematically yield a lower Sa/Vol ratio than a smaller sphere. Hope this helps!

The point is that as soon as the close relationship between volume and mass is broken (e.g. in taxa that have wildly different body shapes, say a snake and a bear) the rule doesn't work anymore. Only if the increase in mass is accompanied by an almmost-equal increase in volume can Bergmann's Rule actually work, but in such cases it works usually fine. Dysmorodrepanis 16:07, 11 September 2007 (UTC)

I'll be glad to add My 2-cents: The RULE is not just a Rule, because you are dealing with: "speciation",.....and climate change, time...so try to make it real compared to what?..All answers aren't Simple.---Also if more rapid Climate changes occurred(a 'minor' Asteroid), a species variation like this along with a Refugium, either Hot, or Cold would certainly change species survivability.(I'm not saying the Rule looks to the Future. It is only a response to distance, from north to south, or from high elevation Cold, to lower elevation hot)(The bottom of the Grand Canyon is a Refugium for Hot species.) A Sonoran-Desert fellow...-Mmcannis (talk) 15:39, 9 December 2007 (UTC)

Later comments:
I think the Australian birds have this scenario. They are in a contiguous range from south(cold), east coast, then north, but they are separated by the interior dry, desert of Australia. I am not sure what species this relates to, but this 'regional' separation(north-east-south) allows for the development of the variation. Maybe somebody could explain the Australian bird species, and help elucidate how "Bergmann's Rule" at least manifests itself in this one specific example area, with the birds(a U–shaped or C–shaped distribution can show a factor required to help yield the B.Rule).... (from the Arizona deserts)-- -Mmcannis (talk) 02:27, 16 February 2008 (UTC)

Volume and Mass

Around sixth grade, most of us learned that volume and mass are two separate concepts. This article uses them interchangably. Please choose one and stick with it, or explain why one is used in place of the other.

Also sixth grade physics: mass=volume*density. Assuming density is constant (and that assumption is implicit in the article), it follows that mass is directly proportional to volume. GregorB 13:02, 17 July 2007 (UTC)

I am unsure how a bird fluffing-up its feathers as a form of insulation would effect: Volume; however doesn't that ability of birds have something to do with survivability ?: Orrrr, does less Surface volume, on a larger but more rounded, spherical form relate to what your discussing? Larger creatures have more mass or weight and therefore more heat capacity, but therefore less surface area because of their rounded form. I personally never even questioned the Bergmann's Rule/Law but I assume that for say, 20 bird species, on say 2 continents, wouldn't there be possibly a lot of suspected factors that are influencing the rule? I assume that there is not 1 factor; and I assume that for 20 bird species, one might isolate about 10 reasons. Maybe two unrelated bird types, but high similarities relating to the causation/of the rule could help elucidate one Major Factor... -Mmcannis (talk) 05:14, 16 February 2008 (UTC)

rewrite

This article needs a complete rewrite. The actual cause of Bergmann's rule is not so clear cut, the whole body mass and radiating heat solution is simply the oldest explanation and not necessarily the correct one. I've tagged the article as factually incorrect and will attempt to rewrite it soon. Sabine's Sunbird talk 21:18, 17 July 2007 (UTC)

I've added Template:Cleanup-rewrite to the article to indicate the above request. Terraxos 14:00, 18 July 2007 (UTC)

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 16:36, 9 November 2007 (UTC)

Humans

Can we really say this holds for humans? Black Africans (other than Pygmies) are often of above-average height. 68.40.65.164 (talk) 04:22, 22 January 2008 (UTC)

Height is irrelevant. Are they above average mass or volume? But, Bergmann's Rule is one of those "all other things being equal" rules. There are too many other differences between human populations this rule to be easily applied. One would expect that if people all had the same general physical proportions, the same diet, the same lifestyle, and all wore the same clothes regardless of latitude, you would see Bergmann's Rule. However, as soon as the people living in colder areas start throwing on more clothes and heating their homes, all bets are off. --76.113.200.14 (talk) 05:00, 1 November 2009 (UTC)

Move?

The other four biological rules have rule instead of Rule; is there any specific reason for this inconsistency? If not, the page should probably be moved. Waltham, The Duke of 20:29, 20 June 2008 (UTC)

Yes it should be moved. --Berland (talk) 17:11, 4 June 2009 (UTC)

Inuit size

You should edit that Inuit size IS actually large. Their limbs are shorter but their body weight is greater than that of white Canadians for example. Thus, you should edit that it doesn't mean that they are smaller, but their body type is different and more robust. — Preceding unsigned comment added by 128.214.163.250 (talk) 11:57, 25 May 2011 (UTC)

 Done Adrian J. Hunter^{(talk•contribs)} 12:35, 25 May 2011 (UTC)

Suggestions for Improvement

A few suggestions for improvement: 1) This page is lacking examples of Bergmann's Rule and it's application for mammals other than humans. I believe if more detailed examples were provided it would be clearer for someone learning about the subject to understand what is going on. 2) The concept of heat dissipation or conservation of metabolic heat has been excluded from the page thus far. An example would be a mammal in a southern desert would want to dissipate heat more readily and therefore would have a smaller mass, or vice versa a larger animal in a northern cold climate would want to use its mass to conserve it's metabolic heat. 3) The criticism of Bergmann's Rule is not noted well on this article as well. Like any rule or hypothesis, in order to understand it better you must be versed in both the pros and cons of the statement. — Preceding unsigned comment added by Owens.977 (talk • contribs) 14:34, 1 October 2014 (UTC)

I have mentioned examples here, but I wonder whether or not the issue, of if lions and tigers in temperate places were bigger than those in tropical areas or not, would be seen as being notable enough to be mention here. Leo1pard (talk) 07:20, 10 December 2017 (UTC)

These would need to be reliably cited, and the fact is curious enough to merit a mention if it will fit in sensibly, but the main take-home point is that examples and illustrations must be chosen to make an article as clear and readable as possible. If there are too many, sometimes it may make sense to create a subsidiary article to list them. Chiswick Chap (talk) 07:50, 10 December 2017 (UTC)

Page views

Leo1pard (talk) 07:20, 10 December 2017 (UTC)

THIS is what passes for science?

The whole idea of Bergmann's rule is preposterous and demonstrably false. When will the scientific establishment cease to adopt baseless speculation as dogma merely because it comes from an august source in the manner of some papal decree? At best the data can be construed as a slight tendency but as a "rule" it is fallacy. Let us phase out this silly notion. — Preceding unsigned comment added by 2405:6582:8580:C00:8F8:EE23:4B25:78B6 (talk) 05:08, 8 December 2018 (UTC)