It’s advent, and that means it’s time for the Zooniverse Advent Calendar. Last year Snapshot Serengeti itself was hiding behind one the doors of the calendar – that means we’re nearly a year old! Today we appear on the 2013 calendar with this post, and the meta-zebra. It’s a thank you to everyone that’s been supporting us for the last year: a zebra made from zebra. Naturally.
This poster was created using a pool of more than 16,000 zebra identified by the Snapshot Serengeti community. We then take a nice, simple capture of a Zebra and use a wonderful piece of software (called Andreamosaic) to generate this poster for you all. It is extremely high resolution (and 70 MB big!) so if you want to, you can print it out to be several feet across! Below is the zebra’s nose.
It’s just a small token of our thanks for a great year. In 2014 we’ll be back with season 7. We also plan to have more fun to share before December is over. Stay tuned!
[Download the full poster here - warning this file is 70 MB big]
By now, you have probably heard of this silly (but hilarious) video that’s been making the rounds of the interwebs lately:
It’s pretty catchy, not just because it’s ridiculous, but because it’s a pretty good question. I mean, how many of you out there have actually ever heard a fox?
The sounds of the bush are one of the many, many things I miss being back here in civilization. From my slightly sketchy corner of Saint Paul, I hear fire crackers and unmuffled engines roaring. Occasionally I get chattered at by an angry squirrel in the back yard. But that’s about it. Nothing like the otherworldly chorus of the Serengeti savanna that Lucy so beautifully described.
The sounds really are incredible and often unbelievable, and I thought I’d share some of them with you. I couldn’t actually figure out how to upload audio files, so I scoured Youtube for the best audio clips I could find and embedded them as videos here.
Zebras: Nothing like horses, these stripy equids sound something like a braying donkey crossed with a barking dog.
Wildebeest: I believe that somewhere in the annals of Zooniverse blogs, there is an audio or video clip of me doing a wildebeest impression. This is better.
Hyenas: Despite being hell-bent on devouring all of my camera traps, these guys are pretty cool. They have a rather large repertoire of very…unusual…vocalizations that are used to communicate in a number of situations. The whoop, which you hear at 0:05 and 0:55, is a long-distance call often used to rally scattered clan members. The laugh at 2:33 is a sign of nervousness or submission. Similar to human voices, hyena vocalizations are individually recognizable to clan-mates. To learn more about hyena vocalizations, check out this blog by hyena expert and director of Masai Mara’s long-term hyena project, Kay Holekamp.
Lions: And finally, for the best, non-hollywood lion roar, scroll about halfway down through our lion research center’s page. This is what they really sound like.
I’ll take any of these noises over the sounds of the city any day.
While procrastinating on this lovely Sunday afternoon, I stumbled across this incredible video of a octopus camouflage in action:
Now, we don’t have anything quite that camouflaged in the Serengeti, but in watching that video my thoughts turned to one of our more strikingly colored species: the zebra. Their starkly contrasting black and white stripes have puzzled researchers and naturalists for a long time.
For starters, the stripes seem like they would be terrible camouflage. I mean, how much more could you stand out from the open plains of waving gold grass? But at dawn and dusk, especially from a distance, the stripes seem to bleed into gray, making them look a surprising lot like elephants (no joke), or rocks, or even nothing at all. Still, up close they still look like bright black-on-white zebras, and it’s hard to imagine that any lion lurking in the thickets nearby would be fooled.
Some researchers have mused that the bold patterns disrupt the perception of predators, and that when the zebras run en masse from an attacking lion, they become a confusing jumble of stripes into which the initial target disappears. Others have pointed out that every zebra has a unique set of stripes, and that these stocky equids might use these patterns to identify herd members, mates, or even mothers (if you’re a hungry foal).
One of the my favorite explanations has always been that the stripes protect against the savanna’s most fearsome creature: the tsetse fly. These blood-sucking insects are not only vectors for some nasty diseases (such as sleeping sickness), but also hurt. A lot. (Having spent more time than I care to remember in the woodlands where these terrible, terrible creatures thrive, just the thought of tsetses makes me shudder. I have spent many hours hurling expletives (fruitlessly) at the tiny terrors.) Tsetse flies suck. A lot. And if wearing stripes were a way to fend them off, I’d have gone out in a zebra suit every day. There are in fact stories of one intrepid researcher back in the day dressing up in a stripey suit and attempting to test whether zebra stripes deter tsetses. But there’s only so much that one man in a zebra outfit can do, and field experiments are notoriously difficult…and so this remained a buried rumor until last year.
Last year, Swedish researchers discovered that horseflies (a close cousin to the terrible tsetse) don’t like stripes. And they tested this on an experiment useing number of fake, plastic zebras painted solid black, solid white, and various things in between. Turns out that the flies really like dark colors over light colors, but still like solid light colors over stripes. And while in the real world, there are things (such as smells) that may attract tsetses to stripey animals despite their off-putting pattern, this study is pretty exciting. And next time I have to venture into the savannah woodlands? You can bet I’m wearing that zebra-striped shirt.
I was asked in the comments to last week’s blog post if I could provide some feedback about the results of Season 4. If you felt like you were seeing a lot of “nothing here” images, you’re right: of the 158,098 unique capture events we showed you, 70% were classified as having no animals in them. That left 47,320 with animals in them to classify, and the vast majority of these (94%) contained just one species. Here’s the breakdown of what was in all those images:
Maybe it won’t surprise you that Season 4 covered 2012’s wet season, when over a million wildebeest, zebra, and Thomson’s gazelle migrate through our study area. I find it interesting that hartebeest are also pretty numerous, but I wonder if it’s because of that one hartebeest that stood in front of the camera for hours on end.
This pie chart is based on the number of what we call “capture events,” which is the set of 1 or 3 pictures you see every time you make a classification. Once a camera has taken a set of pictures, we delay it from triggering again for about a minute. That way we don’t fill up the camera’s memory card with too many repeats of the same animals before we have a chance to replace them. But a minute isn’t a very long time for an animal that has decided to camp out in front of a camera, and so we frequently get sequences of many capture events that are all of the same animal. One of the things we’ll have to do in turning your classifications into valid research results is to figure out how to find these sequences in the data automatically.
Here’s a sequence of an elephant family hanging out around our camera for the night about a year ago. (Hat tip to dms246 who put together a collection of most of these images to answer the concerned question of some classifiers who saw just one image out of the whole sequence: is that elephant dead or just sleeping?)
If you’re interested in how I made the above pie chart, keep reading. But we’re going to get technical here, so if algorithms don’t interest you, feel free to stop.