Introduction  |   Monarch Size & Condition  |  Sex Ratios  |   Researchers  |  Further Questions  |  Vital Statistics

This section includes samples of the kinds of vital statistics that are of interest to monarch researchers. Our goal is to illustrate a few patterns that we have observed, with the hope that these patterns will lead to questions and research projects¾ by you!

One of the most amazing things we have found by measuring monarchs in different locations and times is that they are so variable. For example, the smallest wild monarch we have measured was a male in Mexico, who had a forewing length of 40.0 mm. The largest was a female in Mexico with a winglength of 58.2 mm. Figure 1 illustrates this variation, showing a frequency distribution of winglengths for males and females measured during the summer of 1997. While the average male is larger than the average female (52.2 mm vs. 51.5 mm), you can see that many males are smaller than an average female.  For example, in the picture on the right, the male (bottom) is much smaller than the female (top).

We hope that you are encouraged to collect similar data, or to think of new ways to study monarchs using observations of size, condition, numbers observed, and sex ratios. If you would like to submit your data, we will publish it here. For descriptions of how to measure monarch size and condition, click to our Measuring Monarchs section.