November 15, 2013

Why are these mice shaking their booties?

Pacifica Sommers is a PhD candidate at the University of Arizona. Here she tells us about this unusual mouse behaviour she witnessed when doing research.

By Felicity Muth

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This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American

Pacifica Sommers is a PhD candidate at the University of Arizona. Here she tells us about this unusual mouse behaviour she witnessed when doing research.

What are these mice doing? As I looked through my video data for my doctoral research, I couldn’t help noticing they were, well, shaking their booties. Check it out (the second one has narration):

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I have been using Bushnell Trophy Cams to spy on animals that feed from seed depots I place in Saguaro National Park, outside Tucson, Arizona, for research questions quite unrelated to dancing. But I was captivated by this behavior. Their wild twerking looks energetically costly enough that I wondered if it serves a purpose.

The dancers are probably mostly rock pocket mice (Chaetodipus intermedius). I have videos of them waving their tails in both the Tucson Mountains and in the Rincon Mountains. Few mammologists or animal behavior specialists I have contacted will admit to having seen it. But they have offered several hypotheses on what the pocket mice are doing. These fall in to three general categories:

a) Territoriality: they may be spraying urine to claim the seed depot.

b) Sexuality: males may be smelling a recent female passerby and getting excited.

c) Antipredator: many small animals “flag” their tails at snakes to deter an attack.

Or maybe they’re just thrilled they found 10 whole grams of high carbohydrate millet, and this is their happy dance. These rodents do not need to drink free water after all – they get all the moisture they need from the seeds!

You can learn more about how I would test these hypotheses and why they might matter ecologically over at my blog, www.biodiversitytheblog.wordpress.com.

I welcome more ideas and discussion of what all this dancing is for!

Photo Credit

All photos taken by Pacifica Sommers

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