Tales from Tanzania: So, why do zebras have stripes, like, for real?

Today we saw dozens of very photogenic zebras. This got David and me talking: What came first, the zebra or the stripes?

baby Zebra

There are plenty of theories as to why the zebra has stripes – some more fantastical than others.

According to one African tale, the zebra was once pure white. One very hot day, the zebra went down to a watering hole to drink, but the watering hole was being guarded by a baboon bully who didn’t want to share. The zebra and the baboon got into a fight over the water and during the course of the fight, the zebra backed into the baboon’s fire and tripped. The hot branches left black scorch marks on the zebra’s hide.

While that tale, and others like it, are certainly fun to hear, they aren’t terribly scientific. So what says science?

One popular theory posited is that the stripes act as camouflage, but zebras graze in the open in relatively short grass. The stripes aren’t really making them blend into much of anything.

Another theory is that the stripes make it harder for a predator to pick out an individual from the group. Scientists originally believed that the stripes, when viewed at a distance, would simulate heat waves. Thus, that close-up would be confusing, because all the zebras would blend together. In reality, lions are the main predators of zebras and they generally hunt at night. A zebra’s stripes would, in fact, make them more distinct and visible in the moonlight.

The flip side of this theory says that the stripes help zebras recognize individuals in the larger group. This is actually supported by research, which shows that captive zebras prefer standing next to a patterned wall rather than a solid colored wall, but not 100 percent understood.

A relatively new theory that seems to have some merit is that the zebra’s stripes make excellent fly repellant. Cattle (and zebra too) are more susceptible to illness caused by the tsetse fly, which bite as a reaction to movement and dark colors. In fact, the tsetse fly prefers to bite through dark clothing even when a light, bare arm is available.

To test this theory, one study looked at horsefly bites on horses. They set up five “targets” for the horseflies — one black, one white, one grey, one with horizontal stripes and one with vertical stripes. The great target and the target with the vertical stripes had the least number of bites.

Why? The horsefly, like most insects with compound eyes (including the tsetse fly) has the ability to see polarized light. This improves their ability to see solid and dark colors, allows them to “see” heat signatures and enables them to track moving objects (especially dark ones). Because of these specially adapted eyes, the zebras’ stripes would make them disorienting to the horsefly. The stripes, hypothetically, break up the shape of the zebra and make it harder for the fly to focus in to bite.

While this all sounds great in theory, scientists haven’t conducted these same tests on actual zebras in Africa, but they are pretty positive the results would be the same.

Kwa heri ya kuonana!

Lions and zebra and black rhino, oh my! Join HMNS on an African safari next November

There are some things you just can’t see in your own backyard, or even at the Museum — so our entertaining and informative curators David Temple and Dr. Dirk Van Tuerenhout are bringing a group to Tanzania in November 2013.

The unique eco-system of the Ngorongoro Crater, the vast savannahs of the Serengeti, the forest and grassland near the shores of Lake Manyara, and the renowned anthropological and geological sites at Olduvai Gorge are must-see wonders of east Africa included in this HMNS-exclusive trip.

Herds running across road.HR.RM

This two-week trip includes safaris to superb areas for seeing giraffe, zebra, elephant, hippo, tree-climbing and black-maned lion, black rhino, wildebeest, impala, flamingo, warthog, baboon, and many other species of African wildlife. All are guaranteed a window seat for wildlife viewing in a 4×4 with photo roof. You will also visit the site where the roots of modern man were unearthed by Mary Leakey and a Maasai village.

Dr. Dirk Van Tuerenhout, HMNS curator of anthropology, curated the human evolution section of the new Hall of Paleontology along with numerous special exhibitions, including Lucy’s Legacy: The Hidden Treasures of Ethiopia. He has a special interest in this trip as Africa is the cradle of humanity. Tanzania’s Rift Valley has yielded important early human fossils, landmarks in the evolution of mankind. “We are all descendants of these early Africans. Visiting Tanzania will be a return home for all of us,” Dr. Tuerenhout says.

Maasai Men Jumping 6.HR.RM

David Temple, HMNS associate curator of paleontology, curated the Museum’s new Morian Hall of Paleontology and possesses a wide knowledge base of the evolution of mammals and modern African wildlife. “Tanzania is a perfect destination to learn of the great creatures of the past and witness the great creatures of the present,” he adds. Temple also holds a special interest African history, culture and economic development.

Lioness & cubs in Crater.HR.RM

Space is very limited. For complete itinerary, pricing and registration, click here and mark your calendar for our informational session March 19.

Hey Shutterbugs – Freeze Frame’s for you!

summer-campThe start of Xploration Summer Camps here at the museum are fast approaching. Campers can take week long classes in archaeology, creepy crawlies, the science behind Harry Potter, dinosaurs, robots, crime scene investigation and much more.

In years past we’ve had a camp class called “Photo Safari” that was always really popular. This year we have decided to take one of the kids’ favorite aspects of “Photo Safari” and added new activities and topics — thus, a new camp is born! This year, it’s “Freeze Frame”!

Andrea G., one of our fabulous Summer Camp teachers and a former ExxonMobil Community Summer Jobs program intern for me in Education Collections, is a huge photography buff and she is using her wealth of darkroom knowledge to put together some new projects for the “Freeze Frame” campers this summer!

freeze-frameWe’ll be traveling back in time to experiment with some of the earliest photographic processes, including learning about albumen prints – which originally used eggs!  Using our own darkroom, we’ll build pinhole cameras and shoot black-and-white images and hand-made blueprints. 

Campers will get crafty with Polaroids and image transfers while exploring the artsy side of photography.  Then they’ll turn into scientists, playing with mirrors and light while building their own kaleidoscopes, periscopes, and much more.  Come join us for a bright adventure in “Freeze Frame” this summer!

Just because school is out for the summer doesn’t mean your kids have to stop learning. Check out our Xploration Summer Camps, a fun and educational adventure for your children! These week-long science classes are available for children ages 5 to 12 from June 1 through August 14. For more information, visit our web site at hmns.org.

Blog Contest! What’s YOUR Greatest Adventure?

It’s not often people watch movies at 8:45 a.m., but if you haven’t noticed, the staff at HMNS tends to do things a little differently. You would think that getting to watch a movie at work would be a perk I enjoy, but at 9 a.m. on a Tuesday morning, it’s hard to get inspired. You can imagine my surprise when I recently left the IMAX theatre having planned my summer 2009 vacation, with ideas bouncing around in my head like Mexican jumping beans after viewing Grand Canyon Adventure 3D: River at Risk.

Jamie on safari

Photo Safari in Kreuger National Park, South Africa

I am a huge fan of the outdoors; hiking, camping, biking, rafting, running – you name it! It was pure heaven to watch the adventures of this incredible team unfold as they navigated through the Colorado River via raft, inside of the majesty of the Grand Canyon.

I was reminded of all of the great adventures I’ve been on in the outdoors and all of the knowledge those experiences have brought me. Recently, I went on a Photo Safari in South Africa and was able to view lions, giraffe, rhino, honey badgers, and cheetah among many other animals. My trip affected my outlook on ecology and the effects of the actions of one being on another; it was truly a life-changing experience.

Lion

Doesn’t it look like he’s roaring? Actually,
he’s yawning! If you look you can see the
lionesses lying down with their heads turned
away from the camera. If they were actually
feeling threatened by our presence they
would be rounding up the baby lions
for protection; they are very used to the
jeeps that bring people into the habitat
to observe their lifestyle.

These experiences – the ones that change our habits and perceptions – are a part of growing up, and our continuing education as we move through our life’s journey. Here at the Houston Museum of Natural Science, we believe that part of education is sharing your experience with others – so we’re instituting a giant game of Show and Tell!

Do you have a Great Adventure that’s inspired you and changed your life? Share it with us! You can write an essay (600 words or less) submit a photo slideshow (with captions) or a narrated video (or all three!) – we love creativity and we’re open to pretty much anything that we can post here. Send it to blogadmin@hmns.org. You have until noon on June 27, 2008.

And now, for the best part of any contest…drumroll, please…the following prizes will be awarded to the two most well-versed and meaningful submissions.

Winner, ages 18 and under: a private screening of Grand Canyon Adventure 3D: River at Risk, for you and 50 of your closest friends.

Winner, ages 19 and over: a $300 gift card to REI and twenty passes to see Grand Canyon Adventure 3D: River at Risk.

So get crackin’! We can’t wait to see where you’ve been – and what it taught you.

View contest rules here.

Giraffe

Did you know giraffes are most vulnerable
when they drink? They spread their legs
like they’re doing the splits and lower their
long necks into the water. This position
is stable to accomplish the task at hand
- drinking water – but leaves their long necks
exposed to attack.

safari

African buffalo look and act like cows, but you don’t
want to run into these when you’re on foot.
The trick to being on Safari is staying seated in the
truck. They recognize the vehicle and the people
in it as one being – they don’t recognize
individual parts. In this way, all of these wild
animals have come to accept humans in their
world on a regular basis.

Elephants

African elephants are amazing creatures and this pair
(a young bull and an older male) let us come quite close!
At night when they want to sleep they rest
against giant 8′ termite mounds because they
can’t lay down. When elephants do lay down they must
immediately get up or risk crushing their internal organs
under their own massive weight.