Help us Solve The Mystery of the Danish Underpants

Recently, Pernille Hjort from the Danish Museum of Natural History visited us in Raleigh to exchange ideas about new projects in public science. It was an opportunity for grand scheming, but also to take note of things available in the American South but missing from Danish society. The Danes may have universal health care, free college education and a bike culture that makes biking to work easier than driving, but as Pernille noted, they don’t have turkey vultures, blue birds or robins. But while life in Denmark and the American South may be relatively similar apart from these subtleties there is one thing that is very different, the behavior of cats.

In Denmark, it turns out, all domestic house cats let outdoors walk around and steal underpants, fancy ones at that. We know this because it is precisely what all of the Danish cats in our cat tracker project have done so far although, we have only studied one Danish cat so far, a problem you can help us to remedy by signing up for the project and participating.

The cat in question, Aya, wore one of our Cat Tracker GPS units for two weeks this Spring. Aya has a thieving past, a record, and so as we waited to see where Aya went we also waited to see what he would bring back.  Aya’s behavior provides a rare opportunity to link the movement of an individual predator to the location of its prey. In this unusual case the prey are lacey undies rather than rare birds, but, as has been noted, there are fewer birds to start with in Copenhagen. Cats, it appears, adapt.

On the basis of our observations of Aya when he was wearing a collar, here is what we know:

  • During the tracking period, Aya brought home two dishtowels.
    • The first dishtowel is reported found on 10 March 2015; the item was left outside the cat door and recovered by Aya’s humans the next morning.
    • The second dishtowel was found on 13 March 2015, however it could have been brought home earlier than that date.
  • Aya’s human, Abdi, has no idea where he is collecting these towels, but on the basis of his tracks we can narrow down the potential places the towels are coming from.

You can see evidence of Aya’s past crimes in this video collection. Our designers got creative in imagining Aya’s nights on the town, as you can see in this interactive map* (embedded below). But our hope is that with comments from Aya’s neighbors we can actually hone in on the details of Aya’s nights out.

More importantly, if you are a Danish cat owner and would like to know where your own cat goes, please sign up and participate with cat tracker. With Aya we are working to resolve the mysteries of an individual cat’s stories, but our broader hope in working with the Danish Museum of Natural History and Pernille is to understand what governs the ways in which cats move in places around the world. How important is the breed of cat, the urbaness of the place the cat lives, or the presence of predators of cats (such as coyotes and wolves)? How important is climate?

In essence, we want to understand the global ecology of cat behavior, which may seem as silly as the story about Aya and the underpants, but in as much as cats have become the dominant predator in much of the world has big implications for the future ecology of the places we live, implications that probably depend on which birds live in a place, but maybe also the details of a city, differences in geography or maybe even in the subltleties of human society, cultural differences in how often people leave out food (or clothing), how city blocks are built or even whether or not, in running across the street (as Aya frequently does) a cat has to dodge pick-up trucks or, instead, thousands and thousands of bikes.


*We’re imagining that this is a possible day in the life of Aya, click or hover over each dot to see a note about the stops on his trip (be sure to zoom out, Aya’s travels go far and wide). If you turn on the third visible layer on the map you’ll be able to see an entire week’s worth of trips, a different color for each day.

By |2016-11-22T13:46:44-05:00May 4th, 2015|

About the Author:

Rob Dunn
Rob Dunn is a biologist and writer in the Department of Applied Ecology at North Carolina State University. Central to all of his work is the sense that big discoveries lurk not only in faraway tropical forests, but also in our backyards and even bedrooms. The unknown is large and wonderful and Dunn and his collaborators, students, and postdocs love to spend their days in it.


  1. Avatar
    Sandra Björk May 26, 2015 at 2:05 pm - Reply

    I read of a cat in an icelandic newspaper that also is kleptomanic. A few days later my cat, also in iceland, started bringing knitted things to my moms house. The cat is only 11 months old and comes from a cult of wild cats. My mom is extremely emberrassed about this but I find it rather adorable.

  2. Avatar
    Henrik Kastrup May 27, 2015 at 5:43 am - Reply


    I have a neighbor cat who does the same thing, steals our laundry when it hangs outside for drying, so far it has taken socks and t-shirts.
    our neighbor frequently asks if it is our clothes.

    Best regards,

    Henrik Kastrup

    • Lea Shell
      Lea Shell May 28, 2015 at 2:25 pm - Reply

      Hi Henrik! Email us at — we’d be interested in tracking your neighbor’s cat!

  3. Avatar
    Tom June 7, 2015 at 4:16 pm - Reply

    I’d quite like to track some of my grad students…how big are your collars?

    • Lea Shell
      Lea Shell June 8, 2015 at 10:52 am - Reply

      Collar size varies, but the unit is small and lightweight.

  4. Avatar
    Teri Neville June 21, 2015 at 1:22 pm - Reply

    We have a feral cat that we had neutered several years ago and have been feeding her, but we do not always see her. She only lives outdoors and always comes back to us. We can now pick her up and pet her, she likes having us around. Might be interesting watching a semi-domesticated cat?

  5. Avatar
    Laura Odonnell April 14, 2016 at 2:41 pm - Reply

    I would like to see a key indicating actual distance any of these cats are traveling. I really really love Aya! She is fantastic! Really a gem!

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