A University of Arizona evolutionary biology doctorate student recently discovered an interesting behavior in pocket mice.
Pacifica Sommers has been studying the life cycle of plants and animals in the Sonoran Desert for the past few years. Recently, she wanted to get a first-hand glimpse of the effects invasive species, such as buffelgrass, have on the ecosystem.
She installed night vision cameras in areas where a species called the rock pocket mouse might pass by. Then, Sommers placed a tiny pile of seeds, and waited.
What she saw seemed a little out of the ordinary for a desert mouse: dancing.
"It started to hit me every time I saw the dancing: 'They're doing it again, they're doing it again!'" she explained.
This dancing - or what looked like it - happened after finding the cache of seeds. The mouse would lift up its rear and shake it...pretty vigorously.
Sommers had never seen a mouse react this way before. "I was just thinking, 'What is this?!'" she said.
After posting the video on YouTube, Sommers started hearing theories about the pocket mouse's unusual behavior from other biologists.
“One (biologist said it) was some kind of predator avoidance or anti-predator behavior, like a tail flagging," she said. "Another mammalogist had suggested these may be inexperienced males who were smelling a female and getting excited.”
She then heard from other biologists, who said they had seen female mice do the same tail wigging movement. And, after hearing from dozens of other researchers, Sommer's said the most likely explanation is that this behavior is indeed a scent-marking action. When the mice find the stash of seeds out in the desert, they may be marking the spot with their own scent in order to easily find it again.
“10 grams of millet is a huge resource for a little pocket mouse out in the Sonora Desert," she said. "You can imagine that maybe the mouse (thinks), 'Yes! I got seeds!' and does a little happy dance...the actual secondary effect of them having done that dance is that they mark that area with their scent and they’re able to find it (again later).”