Archive | December 2012

It begins again.

### I’m traveling to Tanzania currently, about to begin my final field season (which will be Season 6 on Snapshot Serengeti). As usual, I’m running terribly behind getting ready to go – so thought I’d share a blog post I wrote while embarking on Season 2. ###

It Begins Again: Wet Season Survey 2011

As I leave Minnesota, winter seems to be already breaking. Amidst the national mid-winter heatwave, mountains of snow are melting, turning the roads into rivers and the hockey rinks back into lakes. For the third time, I am watching cheesy movies across the atlantic, fast forwarding through day and night, racing the sun eastward across the ocean and winning by 30 lengths like Secretariat in the Belmont Stakes.

Just some of the many casualties. Photo taken by Daniel Rosengren.

Just some of the many casualties. Photo taken by Daniel Rosengren.

Except this doesn’t feel spectacular anymore. I am on my way to Tanzania, once again, with 240 lbs of luggage catapulting around the belly of the plane. My back feels thrown and the plane feels cramped, and the woman sitting next to me snorts and sniffles like some Sesame Street character.

After three weeks of delays, I’m finally heading…home? I’m dreading – just a bit – the madness that awaits me in Serengeti. A solid three weeks behind, I have 200 traps to place in the next 10 days….which happens to be humanly impossible.

See, my research relies primarily on camera traps – remote, automatic cameras that are triggered by heat and motion, attached to trees so that they take pictures of wildlife night and day. On the street they’re known as “hyena bait.” On my street anyway.

Yeah, that’s right. I’ve discovered that hyenas are like big ugly puppies – the world is their chew toy. However, unlike your neighbor’s cute, squirmy blue heeler, hyenas have no responsible owner to say “No! No demolishing the $200 camera trap!” Last year alone, hyenas ate nearly $8,000 in cameras. I would arrive at my excruciatingly selected camera site to find bits and pieces of plastic, the stray LED, a fragment of circuit board…just no camera. Elephants took down about $5,000 in cameras, but with minimal destruction. They typically ripped the offending trap from the tree and flung it out of site. Those cameras usually worked, with some minor case modifications. But the hyena victims? Beyond repair.

Given the abysmal loss rates from the first year of this ambitious (crazy?) camera trapping study, I am now returning to the Serengeti with replacement cameras and heavy duty steel protective cases…which happen to weigh about 1.35 tons apiece. That might be an exaggeration, but the point is that they are very, very heavy. And hopefully hyena-proof.

It is dark outside, though the fancy seat-back TV map says we are smack dab over the Atlantic. I feel like my mind should be racing with plans for my research, or meandering down memory lane – but mostly I am thinking about how good the red wine tastes, and how tired my eyes feel. The night outside seems endless, the world feels far away and frozen in time – like Zach used to do on “Saved by the Bell” – and in my alternate reality I slip guiltlessly into mass-market movies, into staring blankly out the window, the wine wrapping its velvet fingers around my fraying neurons.

I have a million things to do by…yesterday, but my brain is tired and does not want to work. I do not want to think about where on earth I put my hard drive, or the fact that I have not yet filed my taxes despite my imminent disappearance into the bush. I want to fade into the bright, apoplectic flashes of the action movie’s runaway trains or the feel-good underdog story of the horse that could. When I get to Serengeti, it will be a flat-out race against the rains. I want to get my cameras set before the rains keep me hamstrung for days at a time. Today is Feb 19; the rains start at the beginning of March. Can it be done? I guess we’ll see when I get there.

Lions: Lazy or just very, very patient?

Lions have a reputation for being profoundly lazy. To the list of inert elements of neon, krypton and argon, it is tempting to add lion. But while lions do sleep for most of the day, they are not idle slackers; they are profoundly patient.

Lions are ambush predators: they lie in wait. There is no need to be antsy during those long hours between hunting opportunities. If a group of lions has caught something recently or failed in a chase, they’ve given away their location, which all the prey in the vicinity will avoid for the rest of the day. But the Serengeti is a moveable feast, and any prey animals that slowly drift in to the area will have little idea of the precise location of danger, if the lions are hiding quietly in tall grass.

 females in the grass
On the other hand, lions do tend to wait around near river courses and rocky outcrops, and herbivores will avoid these spots as much as possible. But if there is only one waterhole in the vicinity, the wildebeest, zebra, warthog and buffalo will have to weigh their thirst against the risks of being eaten, should there be lions hiding in those bushes over there. And if nothing stumbles blindly towards them, hungry lions will eventually have to emerge and actively search for their prey – but not until after dark.

Either way, it’s a game that predators and prey must play every day of their lives, but since lions can easily wait 3-4 days between meals, they have a fundamentally different perspective on the passage of time than the rest of us.

And that’s what makes the camera-trap data so incredibly exciting for me. In the mid-1980’s, I took turns with one of my former graduate students, David Scheel, watching lions 96 consecutive hours twice a month for several years – we were out with the lions for four days in a row just before and after each full moon, squinting through night-vision goggles whenever the moon was above the horizon. I nearly went out of my mind waiting for the lions to catch their next meal. We wanted to find out why lions live in social groups – and we were able to dispense with the myth that lions evolved to become social because of advantages from cooperative hunting: individual females in foraging groups didn’t feed any better than solitary females.

But there were so many more questions that we couldn’t hope to address without a better idea how lions and their prey play that spatial game of cat and mouse around the waterholes. And maybe the prey take advantage of the lions’ territorial behavior by finding refuge in the no-man’s land between pride ranges, or maybe the prey somehow move randomly from nowhere in particular to nowhere else in particular just to keep the lions guessing. A few years ago, Ali Swanson and I found that the Serengeti lions consistently fed better during the dark phase of the moon – what extra steps do the prey take to try to keep safe on those dark, dark nights?

We will finally be able to tackle these ideas with the camera-trap data. In the coming months and years, we will overlay the camera-trap grid on to maps of high-risk features in the landscape and of lion-telemetry sightings, and then we will finally see how the Serengeti herbivores cope with the uncertainties of living with the hidden dangers of those not-so-lazy lions.

Have you spotted a zebra today?

This video is from my first research trip to Serengeti in 2009. I bet you’ve already found some photos of zebras at Snapshot Serengeti. Here’s what they look like moving. (And yes, it was quite windy; sorry for the noise.)

I hope you get paid for that…

Not that long ago, somebody asked me just what it was I was doing at the University of Minnesota. When I described my dissertation research to them, they paused in thoughtful silence, then asked slowly, “Did you ever think about doing something…useful?”

I’m pretty thick-skinned – so that just made me laugh. I love what I do and wouldn’t trade it for the world. But I also think that it really and truly is important. We live increasingly in a world where water comes from the tap, and food from the grocery store. I think it’s important for us to understand how the world works – how all of the puzzle pieces fit together to produce this amazingly vibrant, dynamic mosaic of life…and how our actions might affect it.

And so with that, this post is devoted to all the things that people say when I tell them what I do.  I’m curious to hear the lines that other folks get!

The things people say:

– Huh. Did you ever think about doing something…practical?

– I hope you get paid for that…

– Um…what are you going to do with that?

– So, are you going to be able to get a job?

– You’ve been in school for HOW long?

–  Really? You get to be a “doctor”?

– Oh! Kind of like the Lion King?

But my personal favorite? “You have the BEST job in the whole world!” I usually hear this from tourists while in the field.  They say this from the inside of their air-conditioned cars, on the way back to their hotels with running water and fresh food (that’s been refrigerated!).  I am usually dusty when they tell me this, I am covered in tsetse fly bites and Acacia thorn scratches, my nose is sunburned and my arms ache because my Land Rover has no power steering. Part of me wants to point out to them the fact that most of my day is spent playing with power tools or watching lion sleep, and that this in fact is rather boring.  Part of me wants to point out that I get fresh meat only every 6 weeks, and have no refrigerator to put it in. That my shower is a bucket, and ever since the spitting cobra incident, I’m a little on edge in the ‘bathroom’. That my toilet is outside and sometimes hard to get to because buffalo like to wander through the yard at night. Yes, a part of me wants to point all of these things out to them…but I don’t.  Why? Because in the end…I think they’re right.

Camera Traps are Pretty Cool…

Studying animals in the wild can be incredibly difficult.  In Serengeti, for example, many of the animals we might want to know more about are really shy (like leopards), or aggressive (like buffalo and elephants) — and it’s hard to get close to them to study their behavior.  Furthermore, a lot of the wildlife we study is nocturnal – meaning the animals are active at night, in the dark, when it’s virtually impossible to watch them in any meaningful way.

Enter camera traps to save the day. If you’re a researcher, a hunter, or a wildlife enthusiast, you’ve probably heard about camera traps. These are remotely triggered cameras that are transforming the way people study wildlife. Instead of taking pictures of the animals, the animals take pictures of themselves!

You might be surprised to discover that camera traps have been around for a long time.  A really long time.  In the 1890’s, a fellow named George Shiras developed a system so that wildlife triggered a trip wire, which triggered a flash and the camera shutter – producing the first wildlife “self portraits.” He was pretty creative in inducing the animals to trip the wire – for example, to photograph beavers he would tie the trip wire to a dislodged stick in the beaver’s dam.  When the beaver went to repair the dam, it triggered the camera!

Modern technology is making camera traps better and more affordable. Cameras today are triggered by a combination of heat and motion – so the animals trigger the cameras merely by walking in front of them.  In recent years, the use of camera traps in research has skyrocketed; they are now widely used to identify the presence of rare, endangered, or even presumed-extinct species; they’re used to estimate species densities, patterns of habitat use, predation, and even the relationships between competing species.  Sometimes, the animals caught in cameras have unique markings that allow researchers to identify different individuals – for example, tigers have unique stripes, and leopards and cheetahs have unique spots. But even for animals where this isn’t the case, statisticians are hard at work developing methods capable of dealing with the data that camera traps are pulling in.

All of this means that we can ask really cool questions about a variety of species – but it also means you don’t need to be a scientist – or a statistician – to use camera traps to understand the world around you.  Ever wondered what your backyard wildlife is doing at night? It’s never too late to find out!

Aardwolf vs. Jackal

#### Today I’m excited to bring you a guest post by UMN undergraduate Peter Williams. Peter conducted independent research in the Lion Lab through the University of Minnesota’s directed research program, helping to identify and process some of the early images from the camera trapping survey. You’ll likely see Peter on Talk from time to time. ###

One of my favorite animals of the Serengeti is the aardwolf. This little-known relative of hyenas has an extremely specialized diet—it mostly eats one genus of termite. Aardwolves, about the size of a fox, are not the toughest carnivores. Some other carnivores, such as lions, have been reported to kill aardwolves, and parent aardwolves guard their burrows to prevent jackals from eating their cubs. I wanted to know if the threat of a jackal attack affected aardwolves. Did aardwolves avoid jackals by living in different areas? Or by being active at different times?

To dive into this, I first compiled the camera trap sightings for aardwolves and jackals in a spreadsheet. Each sighting contains tons of information, such as time of day the sighting was taken, distance to the nearest river, how many trees in the area, what the grass cover was like, etc. I made graphs comparing aardwolf sighting to all of these different factors and looked to see if there were any trends. Then I did the same with jackal sightings. Most factors showed no correlation, but there were a few trends that stood out.

One pattern that was extremely clear was nocturnal behavior in aardwolves. Over 90% of the aardwolf sightings occurred between 7:00 pm and 6:00 am. Jackals, on the other hand, were active all day, with a drop in sightings around the heat of the day. It is unlikely that jackals have an effect on when aardwolves are active, especially because the termites that make up the bulk of an aardwolf’s diet only leave the mound at night.

Hourly aardwolf activity graph2

Later, I tried comparing data between the wet season and dry season. For the aardwolves, there was almost no change in where or when they were active. Jackals in the dry season spent a lot of time in grassy areas that weren’t too arid—the same types of places aardwolves live. In the wet season jackals spread out into drier and more open spaces that are less habitable in the dry season. It makes sense that aardwolves would stay put, given how dependent they are on termites. The movement of jackal between seasons, though, is quite interesting.

graph3

To answer my original questions, the presence of jackals doesn’t appear to have a noticeable effect on aardwolf behavior, nor do aardwolves seem to avoid jackals. However, the jackals moving into aardwolf territory in the dry season and back out to more open spaces in the wet season is a fascinating trend that I want to look into more. I didn’t find what I expected, but trying to find answers always leads to more questions.

One Funky Zebra and Other Talk Picks

One week into Snapshot Serengeti and, as our previous post points out, things have been busy! For today’s Zooniverse Advent calendar we have gathered together the top picks of images from Talk. Talk is where you can discuss and gather up cool images from the main site. Click on any of these images to be taken right to Talk (where you can see the images animated, for  start).

Let's start with this awesome dancing bird, spotted by Twitter user @sanderschenk

Let’s start with this awesome dancing bird, spotted by Twitter user @sanderschenk

This Gazelle has stage presence.

This Gazelle has stage presence.

Pretty sure there's a Lion King scene something like this one...

Pretty sure there’s a Lion King scene something like this one…

Most of these animals are chilling - except for that one funky zebra

Most of these animals are chilling – except for that one funky zebra

Group of Cheetahs

Taken by fellow SEO company: there are plenty of examples of these beautiful animals on the site.

As user dms246 says: blick and you'll miss this zebra.

As user dms246 says: blick and you’ll miss this zebra.

Lilac Breasted Roller

First posted to Talk by user artistjillian – this amazing shot is just a sequence of three.

Follow @snapserengeti on Twitter and join our Facebook group for more amazing images and updates on the site.

Three Million

Dear Snapshot Serengeti Community: As of yesterday, you all have made over three million classifications. That’s 3,000,000. That’s unbelievable! (For those of you new to the Zooniverse, a classification represents one person looking at one image. Or, to think of it another way, every time the “Finish” button is clicked, another classification is made.)

And, I have to admit, we really weren’t quite ready for your enthusiasm. I’m sure you’ve noticed those progress bars on the Snapshot Serengeti title page. You know, the ones that show Season 1 being done, Season 3 being almost done, and Season 2 two-thirds of the way done. Snapshot Serengeti hasn’t even been up for a week yet! The bad news is that there’s not much classifying left to do in Seasons 1, 2, and 3. The good news is there’s a Season 4 that we’re working on getting ready.

So what are these “Seasons”? They’re roughly 6-month stretches of images, based on Ali’s field seasons. Season 1 ran from June to November, 2010, and involved a lot of experimentation and damaged cameras, as Ali figured out what camera set-up would survive the animals’ curiosity.

Season 2 ran from January to June 2011. During this time, Ali gradually swapped out cameras with infrared flashes to incandescent flashes for nighttime shots. She found that the infrared night images were just too blurry too much of the time. The incandescent flashes give clearer (and color) images, with the downside that we just get one night image instead of a series of three. Also during Season 2, you can see the famed Serengeti migration in many of the images. Every year, over a million wildebeest, zebra, and Thomson’s gazelles move through the ecosystem, following the rains and new (and presumably yummy) grass. They’re in our study area from about December to April.

Season 3 ran from July 2011 to January 2012. By Season 3, Ali had mastered the camera-trap logistics. (However, we did have some trouble with a hard drive carrying lots of camera trap images that crashed. More on that some other time.)

Season 4, which will be showing up soon, covers February to July, 2012. And Season 5 goes from July to December, 2012. Yes, that’s right: the cameras are snapping away right this minute. Ali will be heading out the Serengeti in early January and will send us back the hard drive with Season 5’s images. We hope to have Season 5 ready for you all by the end of January.

So what now? Well, your amazing speed at classifying means we have the opportunity to refine our algorithm for combining classifications from multiple people. We’ve been making some assumptions about how many people need to see each image to be sure that we get the animals identified correctly. These assumptions are based on some beta testing we did, and I feel good about them. But right now, while you’re waiting for Season 4, we’re going to put some of the Season 1 and Season 3 images back in circulation for more classifications. That way, we can get an even better estimate of how many times we really need to show each image – and, in particular, how these estimates vary for easy, medium, hard, and impossible images.

So thank you for all your classifications these past six days. Please keep classifying images even when the progress bars fill up; we will be using your classifications. And we’ll have Season 4 ready for you soon.

From lions to everything…

The Serengeti lion project was established by George Schaller in 1966; his book, The Serengeti Lion, is a classic.  When I arrived in 1978, it was hard to imagine there was much left to discover about lions, and I only expected to stay in the Serengeti for a few years.   I just planned to answer a few specific questions about lion behavior before moving on to the next species.  My prior research had been on baboons and Japanese macaques, animals that move around a lot and interact with each other throughout the day. Lions sleep in tall grass and are mostly active at night.  Watching lions is a test of patience.

I took it for granted that lions live in complex social groups (“prides” consisting of about six related females, their dependent offspring, and a coalition of 2-3 males that have joined the females from elsewhere).   I wanted to know why pride females raised their cubs together in a creche; how coalition partners competed with each other for mating opportunities; how the whole crowd managed to feed together at kills.

But whereas a lot of the Serengeti lions were mating and feeding those first few years, there were very few cubs in the population, so I decided to continue the study a bit longer.  But as time went by, I became ever more intrigued about the fundamental ecology of these animals. The Serengeti was changing: trees were spreading in the woodlands, the lion population grew by about 50%, but lions were getting harder to find.   The study area contained a dozen prides in a thousand square kilometers; but some of the prides might not be seen for months on end.  I would go out into the field for four days at time, sleeping in the Land Rover, listening for roars, hoping to see an upright lion in the early morning light.

It wasn’t until we started using radio collars in 1984 that we could find our study animals on a daily basis.   The project then grew in previously unimaginable ways.  We could follow lions through the night; we could see where they went when they didn’t want to be seen. And my graduate students and field assistants could hit the ground running, finding lions for themselves their very first day on the job.

We started asking harder questions: Why did lions live in those complex groups? Why did the males have manes? Who fathered the cubs within the pride? What sort of diseases did they catch – and why were some outbreaks more deadly than others?

By then we tracked close to two-dozen prides, and our focus remained primarily on the lions – on their social behavior, their genetics and epidemiology.  It has only been in the past few years that I’ve felt comfortable about expanding our research program into a broader perspective.  Although there are several other long-term studies in the Serengeti, none of them are able to measure their species’ movements in the same degree of detail as the lions.  Cheetah biologists drive around looking for cheetah with patient optimism; hyena biologists watch hyenas at den sites then accept that their nocturnal subjects will wander off to points unknown during the night.  And no one keeps track of individual topi, hartebeest, waterbuck, bushbuck, impala or dikdik – let alone knows the daily life of a specific wildebeest, zebra or gazelle…  There’s not enough research funding in the world to attach enough radio collars on all those species, and it probably wouldn’t be a good idea to tag any of the herbivores who might then stand out a mile in a lion’s territory.

Then we realized that we didn’t have to touch a thing.  We just needed to set up enough camera-traps to get a composite snapshot of the Serengeti.  We received generous funding from the National Science Foundation, which allowed us to set out 225 camera-traps in our study area, but then we faced the problem of how to process the resultant flood of over a million photos a year…

Eat food. Don’t be food.

Imagine you are an impala.

impala

You’re hungry. You want to go find some lovely nice grass to graze, and you know where the tastiest grass is. The only problem is that every time you go over to taste that best grass, you smell lion. And, well, that’s a little scary. So what do you do? Take the chance and go nibble the tastiest of tasty grasses? Or go elsewhere where the grass isn’t quite as nice?

This conflict for herbivores between finding the most nutritious food available and not becoming food is the basis for some of our research questions. We know that lions prioritize certain areas for hunting. In fact, former Lion Research Center researcher Anna Mosser discovered that lions set up their territories near where rivers and streams come together. Here there is open water where herbivores may come to drink and lots of green coffee leaves and vegetation (which is good eating for herbivores, but also provides a place for lions to hide and stalk those herbivores).

We know what the lions do. But what we don’t really know is what sort of decisions the herbivores make. The answer to this question likely depends on the answers to some other questions. We might first ask: what does the distribution of grass look like out in the Serengeti? If it’s the wet season and there’s good grass all around, perhaps we’d expect that herbivores would tend to avoid places with lots of lions. But if it’s the dry season and the only good places to eat are near rivers, then maybe the herbivores are forced to eat near lions so they don’t starve.

Or, we might ask: for any given herbivore species, how likely is it to be attacked by lions? Very large herbivores – like hippos, elephants, and giraffes – are a lot less likely to be attacked by lions than their mid-sized relatives. So maybe these big herbivores don’t care very much about whether they’re eating near lions or not.

We also have to ask the question of whether the herbivores can even tell which areas have a lot of lions and which don’t. If they can’t tell where the lions are, then we’d expect them to spread out, with more herbivores in areas of better foliage and fewer animals where the foliage isn’t so good.

The data you’re giving us through Snapshot Serengeti will help us understand the choices herbivores are making. We’ll be able to map the distributions of lots of different herbivore species. Then we’ll compare the distributions with the areas with the best greenery and the areas where lions congregate. We’ll be able to see if different herbivore species distribute themselves in different ways. And we’ll be able to see, over time, how these herbivore distributions change with dry season, wet season, droughts, and floods.

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