Just to clarify about cat roaming

Yesterday I posted some range maps of Australian cats, showing wide roaming detected by putting GPS sensors on their collars.  (I’ve added one below.) Some readers claimed that the long trips might have been visits to the vet’s, another that virtually all the excursions were “artifacts.” Virtually nobody accepted cat tracks like these:


Well, the study was replicated in England by researchers at the Royal Veterinary College, with 50 cats from a single village, each examined for a day. The study is described here, and some of the range maps are here. There are ten shown; here are three, and if you go to the second link, you can see where the cats were at a given time (the locations were verified with videocameras). Remember that the Aussie cats were tracked for ten days, and the maps below are only a single day.

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Believe the data yet? If you want to raise doubts, maybe it would be good if you actually looked at some studies first, as did reader John M., who called my attention to this study. There’s also a lovely BBC video on the research, “The secret life of the cat,” which you can watch below or on the Vimeo site.


  1. Trevor H
    Posted June 13, 2016 at 2:37 pm | Permalink

    We had an ex-feral cat who went miles away, he was a un-neutered tom though…

    We had 2 labs and he would go waling with us

  2. Kevin
    Posted June 13, 2016 at 2:48 pm | Permalink

    I don’t want to think how far my cat goes. The plus side is, she always comes back and must know a great deal more about the hood than I expected. The downside, she’s got, for all practical purposes, a net zero momentum transfer to automobiles with the outcome not to her advantage.

  3. Posted June 13, 2016 at 2:50 pm | Permalink

    We watched that documentary a couple of years ago. Tonight, we’re watching “The Scret Life of Kittens!”

  4. Randall Schenck
    Posted June 13, 2016 at 2:53 pm | Permalink

    I watched that show when it came out a couple of years ago. I think on PBS as lots of BBC stuff does. It was great and revealed a lot of things about the cats that the owners did not know. As I recall, some cats that overlap with other cats find ways to miss them and avoid confrontations. If they do show up at the same time, there can be trouble.

  5. Mark Sturtevant
    Posted June 13, 2016 at 3:20 pm | Permalink

    I have seen maps like these on PBS.
    My, Hermie seems to be especially busy!

  6. Hempenstein
    Posted June 13, 2016 at 3:28 pm | Permalink

    Didn’t comment on the last one since others had already commented on what I found puzzling – the dead-straight lines over considerable distances. Like, for instance, Sooty’s (in purple). If the read-interval is (say) every half hour, then that explains it all.

    • jahigginbotham
      Posted June 13, 2016 at 5:19 pm | Permalink

      Does anyone know how the data were collected?

      • Gregory Kusnick
        Posted June 13, 2016 at 7:02 pm | Permalink

        I’d like to know as well. The BBC site doesn’t say, nor does it link to the actual research as far as I can see. All we’ve seen so far are popular write-ups of it, so I think it’s reasonable to reserve judgment until more details on the methodology are forthcoming.

  7. ladyatheist
    Posted June 13, 2016 at 3:31 pm | Permalink

    One of my neighbor’s cats poops in my forsythia every day. It really stinks. I wish they’d keep the pooper indoors.

  8. W.Benson
    Posted June 13, 2016 at 3:44 pm | Permalink

    My cats are home bodies. I wonder how much wandering is affected by loose dogs. There are lots where I live.

  9. Posted June 13, 2016 at 5:41 pm | Permalink

    We don’t have a “cat-flap” and our cats are always indoors. If a cat grows up this way sometimes it is afraid to go outside. Our cats are probably missing a lot of fun, but missing danger as well. And the neighborhood rabbits and birds are happier.

    • Posted June 20, 2016 at 4:17 pm | Permalink

      The same with my family and our cat. These maps are impressive but at the same time a little scary, thinking how efficient cats are as predators. I have read about an island bird species (don’t remember the name) made extinct by a single cat, pet of the beacon guard.

  10. Joseph Stans
    Posted June 13, 2016 at 6:09 pm | Permalink

    Donald comments

    On Mon, Jun 13, 2016 at 2:30 PM, Why Evolution Is True wrote:

    > whyevolutionistrue posted: “Yesterday I posted some range maps of > Australian cats, showing wide roaming detected by putting GPS sensors on > their collars. (I’ve added one below.) Some readers claimed that the long > trips might have been visits to the vet’s, another that virtually all” >

  11. Billy Bl.
    Posted June 13, 2016 at 6:26 pm | Permalink

    I had no idea cats roamed so far. After two days up a huge pine and, the next week, four days up a BIG POLE carrying high-voltage power lines, my cat is restricted to inside or a catio. Done roamin’.

  12. Posted June 13, 2016 at 7:04 pm | Permalink

    I saw that BBC documentary some time back and thought it wonderful research. Imagine crowd sourcing that, giving cat owners collars with cameras and GPS trackers aligned to the scientists’ programmed computers, and comparing cats by local geography, urban vs. etc., longhaired vs. shorthaired, and even tabby vs. Siamese. I think it would be fun!

    • Posted June 14, 2016 at 1:44 am | Permalink

      Part of the high school curriculum for Biology back in the day was to devise and carry out an independent field study over vacation.

      I decided to stalk the family cats with an old monochrome reel-to-reel video recorder that belonged to the school.

      Now, I can’t pretend I was particularly diligent or objective, nor did I follow them all around the neighbourhood, but what I did end up with was not inconsistent with those GPS results.

      The end product had a musical soundtrack from various sources with the opening theme music from Mork & Mindy for the opening credits (which came out just that week and not everyone had heard it yet).

      I got a good grade, though I am not sure that it was really deserved, given all the compromises and general lack of ability to follow the subjects everywhere while remaining unnoticed.

      • Posted June 14, 2016 at 8:42 am | Permalink

        I’d have given you a good grade, too: partly for trying, partly for completing, and partly for doing so with such meager technology. You learned how limited you were, how hard a good study might have been, and that you were not completely objective, plus you added the frills of music. I hope you find that video, post it online, and share it with us.

  13. KD33
    Posted June 13, 2016 at 7:24 pm | Permalink

    Not to be a kitty buzzkill (and I don’t mean to create controversy), but these roaming patterns may be related to the fact that cats kill so much wildlife. You’ve probably heard that housecats are a chief cause of decline in about a third of bird species in the U.S. An interesting synopsis is at http://www.wildlifemanagementinstitute.org. This site estimates about 500 million bird kills in the U.S. annually. An Audubon article titled “Cat Owners Turn a Blind Eye to Pets’ Violence” cites up to 3.7 billion bird kills per year. It also mentions a BirdsBeSafe cat collar; anyone using these on their cats? Interestingly, the study you cite says that the cats *don’t* tend to roam into the country to hunt, but rather stay near town. Anyway, kind of bummed I have to think of my fuss-loving kitties as bloodthirsty killing machines. Something else to blame on evolution, I guess …

    • Diane G.
      Posted June 14, 2016 at 4:54 am | Permalink

      Because of the rancor that arises every time this topic is brought up, we try to avoid it here in the interest of harmony. There are indeed a variety of opinions amongst the commentariat. As I’m sure you’re well aware, there are plenty of places on the web where these discussions are held.

      (FWIW, I agree with you about the toll they take on wildlife, and my kitties are now indoor only.)

      • KD33
        Posted June 14, 2016 at 12:25 pm | Permalink

        Thanks. I’m not versed in the history of this topic on this site, but I am a little disappointed that I/we can’t be enlightened by this knowledgable group. I am curious what “opinions” there could be since the data appear pretty clear. A discussion on what it means to be a responsible cat owner would not seem to be out of order (hence my question about the BirdBeSafe). But if that’s been tried and thought too upsetting, I can look elsewhere.

        • Diane G.
          Posted June 14, 2016 at 4:19 pm | Permalink

          Well, we do discuss politics and religion, and gun control, so that’s probably enough dangerous ground for one site.😀 And some people are more outspoken about carbon usage than others, here, as well.

          I had a look at that collar–cool idea, and I’m glad to see they have some data, though I didn’t examine the work to see how robust it is. (And some of those poor moggies looked totally chagrined to be wearing them. 😀 )

          But my immediate response was, what about all the other wildlife? One of my cats specializes in small rodents if she manages to sneak out. Of course there are two sides to that argument as well, the one being that that was cats’ historical role as soon as agriculture and grain storing arose.

          (Another way to reduce the toll on birds by cats is simply to let the latter outside only at night. The birds will tend to be hidden away sleeping, while both kitties and mousies love to roam at night. [Unfortunately, so do coyotes and owls–who in turn serve their role in keeping other spp in check, but I don’t want my cat to be one of the victims.] And when my cats were still allowed some time outside, they were kept inside as much as possible during bird fledging season–pretty much late spring to the middle or end of summer–because fledgling birds are nothing more than vulnerable little appetizers their first few days.)

          Well, for someone who advises not discussing the topic, I’m sure setting a great example, aren’t I? It sounds as if you & I are on the same page, but I don’t come to WEIT to carry on debates that are available all over the web at present on hot-button issues. For the same reason I try to avoid feminist arguments (I support old-school feminism, not the new pomo junk) because they too are tinderboxes. (I fail at that, too, more often than I’d like.) I’m also an ex-smoker, but not militant about it–I remember how much I enjoyed it. I guess I’m just the Rodney King of hot-button issues. 😀 Or a dishrag.

          • Posted June 14, 2016 at 10:46 pm | Permalink

            Once, my cat, Lucky, brought home a nestling. It must have been female, because he’s always had a thing for the ladies. Anyway, I took it from him, googled instructions, nested and fed it, and found a wildlife refuge to take it in. All this time, until the baby bird was fed and napping, Lucky stayed at my elbow. Once the little one was fed and comfortable, he took off.

            This led me to believe the nestling had fallen out of a tree and was at risk of fire ants, so prominent in our area. Lucky brought it home to save it, but still didn’t fully trust me until he saw I was doing alright by it.

            He’s like that.

          • KD33
            Posted June 15, 2016 at 10:16 pm | Permalink

            Diane – thanks, great post! I think we’d have a great time discussing most things. Not a dishrag at all, I’m guessing! All the topics you mentioned are high on my “hot button” list, too, if for slightly odd reasons. Re the cats, I like the nighttime idea, but we have to limit that due to coyote concerns. Stay in touch, and see you o the site …

  14. Bernardo
    Posted June 13, 2016 at 8:59 pm | Permalink

    Hi. My comment has nothing to do with this post, but as I didn’t know how to reach you, and I know you read the comments sometimes, I thought of sharing this news about bird brains. New research suggests birds have a similar cognitive capability to primates and may indeed have a theory of mind


    • Posted June 14, 2016 at 8:56 am | Permalink


    • W.Benson
      Posted June 14, 2016 at 9:43 am | Permalink

      The speaker in the video is Dr. Suzana Herculano-Houzel, professor in biomedical sciences at the Federal University of Rio de Janeiro and coauthor of the linked study.

    • Gregory Kusnick
      Posted June 14, 2016 at 12:48 pm | Permalink

      Jerry’s email address is easily found by Googling or by clicking the links in the sidebar. That’s the preferred method of bringing items to his attention.

  15. Scott Draper
    Posted June 13, 2016 at 9:14 pm | Permalink

    “fuss-loving kitties as bloodthirsty killing machines.”

    Probably less so than their owner, although he delegates the deed to professionals.

  16. Thylacinidae
    Posted June 13, 2016 at 11:06 pm | Permalink

    I have one of those on my dog in case he digs out & runs (husky, retired sled dog, just adopted.) I get odd artifacts all the time with his GPS tracker. Truly panic inducing when it went off the second day I had him…
    It really seems to be tied into the battery level, start seeing artifacts once it hits low charge at 20% and getting worse as things get lower.

  17. Nick Cimdins
    Posted June 14, 2016 at 12:09 am | Permalink

    As a runner who uses GPS technology quite a bit, I’d say that these traces are a combination of the real thing and GPS error. It also depends on how often the device is recording the GPS position – if I had to guess, I’d say the purple plot is set at a much longer interval than the yellow plot. I’m suspicious of any of the long spikes, but presumably if you had data from multiple days, you could discern whether it’s a realistic path, or an error.

    • Posted June 14, 2016 at 4:45 am | Permalink

      They do have video evidence to back up those “long tracks”; it’s in the piece.

      • Alpha Neil
        Posted June 14, 2016 at 5:52 am | Permalink

        I think what Nick is saying is that the spikes look unrealistic due to the sampling interval which makes the paths unnaturally straight between known positions. The purple path cat didn’t walk directly over buildings so the path displayed isn’t the path the cat actually took. This just means that the path traveled is actually longer and the distance traveled greater than the device indicated (more serpentine path). Also, the cameras were fixed so unless there happened to be a camera at the point of the spike (where the cat turned around), the cats arrival exactly at that point is still inferred. The confidence in the accuracy of the “spike” then is dictated by the proximity of the nearest camera that captured the cat on that route. GPS error is very real.

        All that being said, I have no doubt cats range far as I often see a cat in my yard who lives over 350 meters away (straight line, through forest). I think the study did a good job characterizing the movements of cats. Future studies will be even better.

        • Gregory Kusnick
          Posted June 14, 2016 at 11:44 am | Permalink

          “The purple path cat didn’t walk directly over buildings so the path displayed isn’t the path the cat actually took.”

          Yes, exactly. If the actual data consists of disconnected points at infrequent intervals, then it’s misleading to present them as connected paths.

  18. Charles Minus
    Posted June 14, 2016 at 12:13 am | Permalink

    I live in Long Beach, CA, a city we share with some very beautiful and hungry coyotes. If someone were to attempt this map project here, I’m afraid a lot of those lines would end mid-circuit.

  19. infiniteimprobabilit
    Posted June 14, 2016 at 1:52 am | Permalink

    The top illustration on this page wasn’t the one that drew the doubt in the previous post. The long excursion to the north is well attested by little kinks in the yellow line suggesting it’s genuine.

    What people doubted were some of the tracks that ran in an apparent dead straight bee-line across the grain of the terrain to some single far-distant point and back, with no apparent intermediate points.


  20. p. puk
    Posted June 14, 2016 at 8:52 am | Permalink

    The further a cat roams the more wildlife it’s killing.

    Just sayin’.

    • W.Benson
      Posted June 14, 2016 at 9:45 am | Permalink

      Not necessarily. It may be a Tom visiting lady friends.

      • Posted June 14, 2016 at 9:50 am | Permalink

        Those roaming ranges might also represent the spread of bird feeders, so perhaps fewer birds are killed because the cats have to spend so much time traveling between feeders where birds are clustered.

        I deliberately put a bird feeder in my yard to keep my cats close (before they were strict house cats). I just made sure the feeder was out of reach, whether by jumping or by climbing above and reaching down.

        Now, I put catfood out, level with a window, and the birds come to eat the catfood where the cats can see them quite up close. A young squirrel came, two days ago, and an adult squirrel, yesterday. How convenient that all eat the same food, LOL!

      • gravelinspector-Aidan
        Posted June 14, 2016 at 10:06 pm | Permalink

        … and partaking of a post-coital snack?

  21. gravelinspector-Aidan
    Posted June 14, 2016 at 10:20 pm | Permalink

    Scaling the first (Australian) plot to the UK ones by reckoning the residential roads to be similar sizes, the main parts of the home ranges seem to be of similar sizes.
    The questions about he original data (and this second set) from me were more about GPS precision and sampling issues. Most of the basic range data seemed reasonable. And yes, I did see the UK programme approximately when it came out. Whenever I’ve had to look at raw GPS data sets (either from my standalone, when I had that, or from tablet or phone or camera more recently), there have always been artefacts like this – sometimes up to several kilometres – that I need to clear out of the dataset before using it to geolocate photographs of (for example) rock outcrops. GPS is not a panacaea for understanding one’s location.

    • infiniteimprobabilit
      Posted June 14, 2016 at 10:59 pm | Permalink

      “GPS is not a panacaea for understanding one’s location.”

      I’ll second that!


      • gravelinspector-Aidan
        Posted June 14, 2016 at 11:23 pm | Permalink

        I’m trying to remember a track … something about “Stand in the place where you are …”, which always made me feel like checking my pockets for map and compass.
        And yes, I have navigated in places with strongly variably magnetic bedrock, and compass variations of over 90 degrees over a few metres. Compass and map aren’t a panacea either.
        “I met a traveller in an antique land /
        Who said “I’m lost” /
        And after I’d fed and cuppa’d him, /
        … we worked out he’d been 40 miles off route during his day’s walking.
        The RED end points north.

        • infiniteimprobabilit
          Posted June 15, 2016 at 12:10 am | Permalink


          I once drove across northern Italy in an afternoon, from Belluno Nord to Col du Lautaret across the French border, on a completely different autostrade from the one I thought I was on. It wasn’t till after I got home that I worked out, from memory and with the aid of Google Streetview and a couple of photographs, where I’d been. (And it explained why I’d never noticed passing Milan).


          • gravelinspector-Aidan
            Posted June 15, 2016 at 1:56 am | Permalink

            I was driving up a road I know well – very well – a couple of months ago and I discovered that one of the motorway-motorway junctions was full of roadworks. It took me 2 hours to get off the motorway, into the city centre, out of the city, back onto the motorway in the opposite direction, and eventually to avoid repeating the problem by navigating by the Moon until I was far enough off my original route to turn the SatNav back on.
            I’d noticed the warnings bout roadworks. I should have stopped at the preceding service station for a coffee and a consultation.

            • Diane G.
              Posted June 15, 2016 at 2:09 am | Permalink


              Many years ago I was driving the back roads up to my son’s university when I came to a 5-way intersection and wasn’t sure which spoke to pick. But I did know where the stars were that time of night in that season, so I picked the spoke that led away at the correct angle I knew I should be heading in. From then on I enjoyed driving the back roads at night and navigating by the stars.

              (Out in the countryside, obviously–where you can still see them!)

              • infiniteimprobabilit
                Posted June 15, 2016 at 3:26 am | Permalink

                Heh, that same trip I mentioned, I left my friends at the hotel in the south of France to go for a little drive, I recognised a couple of intersections I’d seen when reconnoitring on Panoramio (this was beyond the range of Google Streetview) so was tempted further into the wilds, I’d left my large-scale Michelin map behind at the hotel but I remembered enough to navigate myself in a big loop on gravel roads / tracks, aided later by the rising moon. Got back to the hotel at 10p.m. feeling quite smug, not least because my friends couldn’t criticise me too much for my absence, they would have loved the drive too. (Moustiers – St Jurs – over the Col de St Jurs and a big loop around both sides of the valley of the Estoublaisse to Majastres – upland country, and noble views).

                I have fond memories of experiences like that.

                (Actually, I’m off tomorrow to the same area, unfortunately with family in tow so my style will be severely crapmed)


              • Posted June 15, 2016 at 9:27 am | Permalink

                That is WAY cool!!!

              • gravelinspector-Aidan
                Posted June 15, 2016 at 11:39 am | Permalink

                One of these days I’m going to introduce the wife to the Magic Roundabout (the name will be more redolent to British readers of “a certain age”) in Swindon.
                Yes, that is 5 roundabouts on the periphery of a contra-rotating roundabout. It is “interesting,” particularly if you’re not expecting it.

              • infiniteimprobabilit
                Posted June 15, 2016 at 7:11 pm | Permalink

                May I throw into the ring, the Place de l’Etoile (aka Place Charles de Gaulle) around the Arc de Triomphe in Paris. Twelve connecting streets, six lanes of traffic, no road markings and no traffic lights. And it works. The first time I saw it (as a pedestrian) I was staggered. “My gawd. I’d _never_ drive round that!” Which sentiment predictably lasted about ten minutes. A year later I did exactly that, and Parisian drivers are extremely good, every single one of them managed not to collide with me. 🙂


  22. Posted June 17, 2016 at 5:21 pm | Permalink

    Why such a large range for an ambush predator? Imagine how larger ranges cursorial predators need. No wander they cannot co-exist with humans today.

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