About Me....


Cara with a house wrenMy name is Cara Krieg and I'm a graduate student in Dr. Tom  Getty's lab at Michigan State University.  I'm fascinated by    behaviors scientists don't expect.  For my dissertation work I'm studying two behaviors - female-female aggression and female song - in a population of Michigan house wrens.

Above: A male house wren poses for the camera (summer 2011)

Recent developments...

About my work....

    In many human societies men are stereotyped as competitive and aggressive while females are stereotyped as more passive and nurturing.  In the scientific world, scientists expect males to evolve competitive behaviors and elaborate traits like colorful feathers and song because they often compete intensely for mates.  Sexually selected traits are not expected in females except in rare breeding systems.  As a result, these female traits have received very little research attention compared to males.

    However, it turns out these female behaviors are a lot more common than scientists first expected (for more information check out Rosvall 2011, Clutton-Brock 2009 or 2007).  Females frequently compete intensely - even to the point of injury and death - in species in common breeding systems.  New reports of singing females are published every year, even though we originally though female song was quite rare in temperate latitudes.  There is now evidence that the female ancestor of the entire songbird family was capable of song (Odom et al. 2014).  Females have been singing for millions of years!

House wrens display both of these female behaviors.  In my research I'm trying to understand why these female behaviors exist and why they might be different from males.  Do they help females gain and protect valuable nesting sites?  Do more aggressive females make better moms?  What about survival or health?  Do aggressive females suffer some cost to this behavior?  Does a female's song communicate something about her physical condition or fighting ability?

Why I do it...

I think this work has important implications beyond the science for both the general public and the scientific community.  Nature is often used to justify culturally constructed gender roles as "natural".  I think it's important for students to see that while our species may display particular behavioral norms, nature shows a whole range of variation.

I think work like mine also highlights the importance of perspective in science.  Although scientists like to think of ourselves as completely unbiased observers in search of the truth, the questions we ask, the things that catch our eye, and even how we explain our results can be heavily influenced by what we expect.  Females have been showing these behaviors for a long time but it many cases they were only just noticed, possibly because we never expected them.  I think this highlights the enormous benefit the scientific community gets from involvng many different kinds of researchers with many different perspectives in the scientific process. 

On a more personal note, I've always loved the outdoors and I've been obsessed with animals for as long as I can remember.  Field work gives me a chance to really get to know my organism and teaching gives me a chance to pass on this sense of wonder to others!

Left: Waiting for a female house wren to fly into a mist net at my field site; Right: Enjoying the great outdoors in the Boundary Waters Canoe Area Wilderness             

watching wrens fly the mist net   boundary waters


  • Rosvall, K.A. 2011. Intrasexual competition in females: evidence for sexual selection? Behav Ecol 22:1131-1140.
  • Clutton-Brock, T. 2009. Sexual selection in females. Anim Behav 77:3-11.
  • Clutton-Brock, T. 2007. Sexual selection in males and females. Science 318:1882-1885.