ļ»æI am NOT a cat person, but I gotta say, catsĀ
are kinda crushing it out there. All over the world, cat populations continue to grow while mostĀ
wild predators are in steep decline. Apart from dogs, cats are the mostĀ
abundant predatory mammals the world has ever seen. There are between 600 millionĀ
and a BILLION domestic cats in the world. But hereās the thing: we actually have no ideaĀ
what cats are doing when we are not around.Ā Which is a pretty typical cat thing, right?
So I met up with some scientists conducting not only the biggest study of cat movementĀ
in the world, but the largest tracking study of any species - to find out whatĀ
exactly cats are doing out there. Iām Shane Campbell-Staton, andĀ
this is Human Footprint. You actually own cats.
Iā We have four cats here in the house. I'm not sure own is the proper verb.
Okay, hahaha.
Ā But they live here. And they runĀ
the show, put it that way. In the biology world, Jonathan is aĀ
legend for his research on lizards. But outside the lab, cats are his passion.
Iāve always been into cats, but it never occurred to me to do anything professionally withĀ
them, because theyāre just cats! But he just couldnāt help himself. And now, heāsĀ
written a whole book on the science of cats. So how do we get from the truly wild cat to theseĀ
guys that are running around your house? The idea is this: that when humansĀ
adopted an agricultural lifestyle, we started raising crops and storing them; andĀ
that of course attracted rodents, and this was in the native range of the African Wild Cat.
These wild cats started hanging around human settlements. The less afraid of us theyĀ
were, the better they did. Over time, cats evolved to be friendlier, or atĀ
least more tolerant of human company. We started appreciating them too, and soon, weĀ
were bringing them with us around the world.
Ā Let me see one of these cats.
All right. I'll go get one rightĀ here. He's in his little basket overĀ
here. It's showtime, Nelson. This is Nelson. He's the one on your mug. Let me see what all this noise is about.
Now if I look uncomfortable here, itās because I'm very allergic to cats.
A key phase in domestication, in general, is when humans take over the breeding process.
Cats became semi-domestic simply by hanging around and catching mice. Itās only for theĀ
last few hundred years that we've controlled who mated with whom, producing dozens of distinctĀ
breedsā¦like the American Burmese in my lap. Here you go Nelson, Iāll putĀ
you back in your basket. I know I'm going to pay for that later.
So you mentioned that a couple of your cats are inside/outside cats. When they're outĀ
cruising, do you have any idea what they're doing out there?
Well, mostly no. He says, "None of your businessĀ
is what I'm doing out there."
Ā Cats would be appalled to knowĀ
that researchers are working hard to uncover their secret lives outdoors.
Roland Kays knows more about animal tracking than almost anyone on the planet. What he getsĀ
up to in his own timeā¦ thatās his business.
Ā Hey, welcome.
Hey, how's it going? Thank the good Lord for antihistamines.Ā
āCause this was not in my contract. Is this not the perfect placeĀ
to talk about cats? There's definitely a lot of cats in here.
It's a cat coffee shop. And if you want to, you can walk out of here with your very own cat.
Okay. Iā¦ will pass, but I appreciate the sentiment.
You know youāve got too many cats when you start giving them away for free.
When cats go out, cats hunt, right? I mean this is why we domesticated them in the first place.Ā
One cat catching a few things isn't a big deal, it's when you magnify that by 600 million, thenĀ
all of a sudden, maybe it is a big dealā¦ The problem is, scientists know next toĀ
nothing about what cats do in the wild, or what their impact might be.
Rolandās answer? Track cats the way we track wild predators ā by fittingĀ
them with GPS-enabled collars. Several of those cats were right here inĀ
Raleigh, including a cat named Kraken. Hello.
Hey, how are you? Good, how are you?
Come on in. So she came to us as a stray in the summer,Ā
before we decided to ā¦ bring her inside. Is it like a mystery to you whatĀ
her life is like out there? Oh, yeah. Absolutely. I found out aboutĀ
Mohammed's study, and so we signed her up. So this is the tracker that we are using on theĀ
cats. What we have here is the microchip that has both the accelerometer and the GPS.
The accelerometer measures the cat's movement - left-right, forward-reverse.Ā
And the GPS tells us where the cat is. We save the data on the collar, then we retrieveĀ
it from the animal. Then connect it to a computer to download the saved data here.
So a cat has to bring you the data back? Yeah.
With this study, what will we know about the lives of theseĀ
cats that we didn't know before? Well, one of the things that we're hoping theĀ
more detailed data will show us is, where exactly they're going and what habitats they're using, howĀ
often they're crossing streets, for example. And if they're going into the natural areasĀ
where they might on one hand encounter a coyote or something scary, but also could potentiallyĀ
be hunting native species that would be more concerned about out in a more natural area thanĀ
compared to the more neighborhood urban area. So understanding exactly where the catsĀ
go and also what their behavior is. Cool. So should we release the Kraken?Ā
I'm so glad I got to say that. I think this is Kraken right hereā¦
It went down here to this house, and then it came back, and you can see one trekĀ
way over there. That was a bit of a surprise. Rolandās study isnāt just the biggest study ofĀ
cat movement in the world - it's the largest tracking study of any species. Roland sent GPSĀ
collars to collaborators all over the world. So this is just a map of theĀ
earth, and I've got pink dots anywhere that we were tracking cats.
So, we've got Allie, Aley, Amber Rose, Amelia, just A to Z probably we'veĀ
got all kinds of different ones. It turns out, most cats donātĀ
stray too far from home. Our average across all 900Ā
cats was 3.5 hectares. Thatās about six or seven football fields.
The next thing we had to figure out is, how do we put that into perspective?
Roland compared data from domestic cats to their closest wild relatives.
What we found was that the domestic cats have a four to ten times more ecologicalĀ
impact on their prey than do wild species, but that's going to be concentrated withinĀ
basically 100 meters of someone's house. One of their biggest footprints can beĀ
seen on migrating bird populations. There are some estimates in the United StatesĀ
that cats kill sort of one to three billion birds a year.
Billion. Yes. But itās even more small mammals.Ā
Itās like 7-10 billion small mammals. And the impacts of cats in placesĀ
like Australia, New Zealand, and oceanic islands have been devastating.
There are examples of animals that have been completely hunted to extinction by cats.
Some biologists consider them the worst invasive species alive. But Rolandās got a plan to curb theĀ
impact of these cuddly killers. It could start by adding an accelerometer to our catsā collars.
The accelerometer basically measures the orientation and the movement of theĀ
collar in three dimensions. So now, here's the three axes, X, Y,Ā
and Z axis, and you can see they're very flat. That means the animal's resting.
So here, you can see, see how rhythmic this is. Choo-choo-choo-choo-choo-choo-choo-choo-choo.Ā
So that's a walking or running cat. If the accelerometer can recognize a walkingĀ
or running cat, what else can it tell us? And so what our goal is, is to get artificialĀ
intelligence algorithms on the collar recognizing, this cat's about to hunt.
One of the amazing things, so birds have alarm calls, and they listenĀ
to each other. So they know, like a chickadee knows the alarm call of the titmouse.
So we could have basically a bird alarm call go off on the cat's collars and all the birdsĀ
would be alerted, "Look out, predator here." It seems an ingenious solution, butĀ
the flip side is that also, cats learn. Is it possible that cats will justĀ
learn to hunt a different way? I'd say it's highly possible that IĀ
would be outsmarted by a cat, yes. Because cats learn. If you give aĀ
cat a bell, it learns how to walk without triggering the bell.
And so, itās possible that it could figure out that when it does a certain thing,Ā
thereās this noise that comes from its collar. I donāt know. We'll have to wait and see.
But I guess the difference is that the bell doesn't have the ability to adapt to the cat.
Exactly. Exactly. But an AI potentially has the ability toĀ
adapt and learn along with the cat. Yup, yeah.
That's brilliant. Thatās really cool. Weāve made a pact with cats. Even as theyĀ
deplete the natural world around us, they seem to enrich another part of our lives.
Sure, their modern existence can be pretty bizarre, and damn do they make my eyes itchā¦
But compared to their wild relatives, one thingās for sure: cats are evolutionary winners.
If you want more Human Footprint, you can tune in to the full length series on the PBSĀ
App or on your local PBS station.
Ā Check out the link in the description to watch aĀ
full episode and to find out more about the show.