I got married in Amsterdam. One thing I remember most about my time in The Netherlands is the obvious height of the locals. Both men and women, generally, are quite tall.
A new study supports my anecdotal observation. Dutch men are the tallest people in the World (women there are second), followed closely by some of their European neighbors. People in Southeast Asian and African countries are, on the other hand, shorter.
I’ve always wondered why the Dutch are so tall. Is it their dairy-rich diet, perhaps? Or could there be a correlation between the lower average temperatures in Northern Europe and its apparent height advantage? Are people taller in colder countries?
The answer is … sort of.
If you examine the relationship between a country’s average male height and its average annual temperature, there is a modest inverse correlation. Or, about half of the taller populations can be explained by colder temperatures. Other factors certainly apply. (Aside from the statistics, this is a fun but crude exercise. More on that in a moment).
This chart below shows countries’ average height (vertical axis) and average temperature (horizontal axis), and how they relate — with colored dots indicating each nation’s region as defined by the World Health Organization:
Again, there’s not a strong statistical correlation. But the chart is still interesting. Men in many European countries are taller than the world average — and they live in climates that are somewhat colder on average. People in some Middle Eastern countries — Syria, Jordan, Lebanon and Iraq — are clustered around the average of both measures. (Men in Israel, interestingly, are taller). And it’s clear that in some parts of Asia and Africa that have hotter climates, the men are shorter.
Explore the data (there’s a table at the bottom of this post) for yourself. Below is another version of the chart, but with colored dots indicating each country’s income, according to the WHO’s wealth categories:
In this case, wealthy countries do seem more likely to be higher on the average height axis, perhaps because of Europe — an observation that deserves more examination. I’ll save that for another day.
As I mentioned, this is a crude way to ask such a question, which researchers have tackled before in more depth. Take Allen’s Rule, for example, which gets at the question more broadly. It found that “endothermic animals with the same body volume should have different surface areas that will either aid or impede their heat dissipation.”
Here are some of the obvious problems with this analysis. First, using the average temperature of places like the United States or China (or any geographic unit that covers huge and climatically diverse swaths of the globe) isn’t ideal. But that’s the data I had readily available. And if one assumes such a correlation between height and heat is linked to human evolution in particular climates, using the current nation state boundaries doesn’t account for the mass migration of recent human history. I’m looking at you, America and Australia, among others. Also, what about diet, health, wealth, etc.? I could go on…
Think of this post as more of a data exercise, not science. In the end, I just wanted to make a scatterplot using NPR’s lovely dailygraphics rig — and I was a little geeked about the new height data set.
As I mentioned, here’s all the data in a table (note that a few countries were excluded because they weren’t listed in one of the height, climate and/or region/income data sets):