About Guest Contributor

From distinguished lecturers to scientific scholars to visiting curators to volunteers to leaders in their respective fields, we often invite guest authors to contribute content to our blog. You'll find a wealth of information written by these fascinating individuals as we seek to expand your level of knowledge with every post.

Animal Espionage: Meet the Spies, Traitors and Saboteurs of the Wild

by Greta Brannan Rimpo

This week, you’ll have the first chance to experience our new special exhibit, Spies, Traitors, and Saboteurs: Fear and Freedom in America – examining nine major periods in U.S. history when America faced threats from enemies within our borders. But did you know HMNS already features a few “sneaks” of our own? They’re just of the animal variety!

In our HMNS Outreach Programs, we highlight several examples of crafty creatures who have adapted creatively to their environments to prolong survival. Want to meet a few of these smart cookies? Come to our free Shell Educators’ Preview Sept. 29!

How do you become a spy? First, blend in!


Our first spy is a familiar animal to the Gulf Coast – the American alligator! One of the alligator’s strongest adaptations is its amazing camouflage. I remember fishing as a kid on the Sabine River and my dad pointing out a gator in the distance. I tried and tried, but I just couldn’t spot it! Only as we neared could I see the bumpy “dead log” silently watching us float by. Alligators are extremely well-adapted to ambush. With nostrils that stick out of the water like a snorkel and a clear inner eyelid to protect their eyes while they swim, their whole body can stay submerged as they await their prey. While too dangerous to approach in their natural habitat, our Wildlife On Wheels program Texas Wildlife often includes one of our baby alligators, still small enough to keep safely!


Several of our other spies star in our Bugs On Wheels: Amazing Arthropods program and are masters of disguise. The giant long-legged katydid, for example, is the world’s largest katydid, native to Malaysia. These awesome insects mimic leaves, and during the daylight hours they can safely remain motionless, cloaked in foliage, waiting to become active at night. They don’t only come in green though; these insects can have an endless array of shades and patterns to match the leaves of their unique habitats. And like many things that get better with age, so does their camouflage, as their back edge grows brown and tattered like an old leaf.

Traitors mean false friends.


In the natural world, traitors come in many guises, even that of seemingly innocuous plants! The pitcher plant, masquerading as a source of tasty nectar, lures in insects (sometimes even rodents) and traps them. Their victims cannot escape the waxy walls and sticky fluid inside. As their prey drowns, digestive enzymes help break down the body, allowing the plant to absorb the released nitrogen. You can meet three species of this unusual carnivore in our Cockrell Butterfly Center!


Another unique traitor native to our state is the Texas tortoise, often seen in our Wildlife On Wheels programs, though a threatened species in the state of Texas. Deceptively fierce, this desert dweller is extremely territorial, and males will fight to the death if a fellow tortoise challenges. Competitors rise up on front legs to charge, using the pronged gular scutes protruding from the shell to hook under the trespasser, attempting to flip him over. This is a deadly situation for a tortoise as all of the animal’s internal organs press down on the lungs, which causes him to suffocate if he cannot turn back over. Yikes!

The Science of Sabotage


Crushing prey with an estimated force of 60,000 Newtons, the bite of Tyrannosaurus rex would be lethal enough as it is, but some paleontologists, such as Farlow and Abler, debate that a more insidious biological superweapon could be concealed in those fearsome teeth. Fine serrations in each tooth provided strength and cutting power, but may have also allowed meat from T. rex’s last meal to linger, lending a perfect source for bacteria to feed on. Similar to that of a Komodo dragon, it is theorized that the bite of T. rex could deposit overwhelming amounts of bacteria, causing the wound to fester and become septic. Want to touch a T. rex tooth and feel the serrations? (We promise, ours are clean.) A visit from Dinosaur Discovery, part of Chevron Earth Science On Wheels, makes it possible!



Our last saboteur certainly employs a most unusual method of dispatching enemies —how about getting licked to death! The lightning whelk, a carnivorous snail, uses the sharp edge of its shell to pry apart bivalves. Once open, the whelk uses its radula (think scratchy cat tongue, but much worse!) to lick and scrape the hapless victim into smaller pieces for consumption. Fun fact: this ruthless snail is the state shell of Texas, and can often be found on gulf coast beaches. Look for a “left-handed” (sinistral) shell, shaped so it’s easier to put your left hand in. Another great place to see a whelk? In our Wildlife On Wheels: Invertebrates program, or in the Strake Hall of Malacology!

Interested in bringing these super-cool, sneaky creatures to your school or group? Send an email to outreach@hmns.org or call (713) 639-4758 to book your Outreach Program today!

Editor’s Note: Greta is Outreach Coordinator for the Houston Museum of Natural Science.

Una Visita al Templo Mayor: HMNS Discovery Guide experiences Mexico City

by “Cretaceous” Chris Wells

It was late morning and the air was still cool and refreshing as my girlfriend, Fernanda, and I walked through the historic center of Mexico City. I had not expected the weather to be so fair, and in truth there would would be the dry, white sun to contend with shortly. But in the shade of the decaying colonial structures around us, it was very pleasant. The interiors of these buildings were made up in modern styles for the tourists, but the facades betrayed every bit of their declined elegance. The old homes and businesses were grey or red or blue and rose abruptly from varying distances and angles from the street, the structures so old and quirky they felt like natural formations. In their shadows, it felt like we were passing through a cavern. Well… a cavern with a skylight.


The cavernous space between the buildings of the historic districts.

It was all really exotic to me, and on top of that, the streets were packed with people who were heading towards the National Plaza where thousands were gathering to watch Mexico play Brazil in the World Cup. For the viewing pleasure of these masses, three enormous screens had been erected among the old seats of government — grand and impressive buildings whose facades had once been a purer off-white but had since been corrupted by dirt and grime into a shade of gray. In these surroundings, the screens didn’t seem at all out of place because the game was as much a symbol of national pride as any politician. Perhaps more so.


Zocalo Square (AKA the National Plaza).

It was our first international trip together. Fernanda is Brazilian, and of course she wanted to stay and watch the game a little, but I was much more excited about something else. I’ve studied Latin American history in college for years. It’s my favorite subject. Earlier on the trip, we had visited the ancient city of Teotihuacán, one of the oldest centers of civilization in the Americas, and the Museo Nacional de Antropología, which holds some of the finest collections of Mexican indigenous artifacts in the world — artifacts from the Aztec and Mayan cultures and many other civilizations history books have chosen to forget. We had even seen the palace of the Emperors of Mexico, lording over the city from atop a mountain, its grounds adorned with grim-faced marble statues of men holding machetes, the men who had helped bring an end to that decadent age. But all the amazing things we had seen did not compare to the place we were about to visit: the Templo Mayor.


The cathedral built almost directly over the old Templo Mayor. Christianity triumphs over the pagan gods of the Aztecs.

Forgetting my usual policy of early relationship affability, I insisted we press on, past the crowded plaza and cheering fans, past the gloomy cathedral the Spanish had placed at the head of the plaza, to what looked like a pile of rocks huddled behind a fence. This, the old pyramid’s foundations, was all that remained of the most important religious site in Tenochtitlan, the ancient capital city of the Aztec Empire. The conquistador Hernando Cortéz and his men had been efficient in their practice of dismantling the structures of the old city and using the stones to build the new Spanish capital. Of course, by the time he had captured Tenochtitlan for the second and final time, most of the buildings had been destroyed by the cannon balls with which Cortéz had bombarded the city into submission.


From farther away, the cathedral towers over the remains of the Templo Mayor.

But there was still much left to see. Portions of the lower parts of the walls were preserved, rising about twenty feet in the air in all directions and angles. If the Spanish city felt like a cavern, the Templo Mayor looked more like a windswept, craggy range of mountains, like those found in the Antarctic. The unnatural angles were created by people plundering the architecture for building materials over the years since the fall of Tenochtitlan. I got a cold impression from that place, even with the white sun burning the back of my neck.


Serpent head surrounded by two braziers, originally it would have guarded the Templo, which once rose behind it.

We approached what was left of the two stairways that had originally led up to the two shrines at the head of the temple. One shrine was for Huitzilopochtli, the sun god and another was for Tlaloc, the god of rain and thunderstorms. Today, the stairs rise about 20 feet before ending abruptly in crumbly, eroded peaks. Originally, they would have ascended 300 feet. At the base of these stairs, we were greeted by serpents’ heads carved at the foot of the stairways on either side — Quetzalcoatl, the feathered serpent, whom Cortéz was mistaken for by King Moctezuma. This case of mistaken identity is why Cortéz and his men were able to march unimpeded into the city. Many of Moctezuma’s commanders and trusted officials had advised against it, saying the Spanish should be treated like an enemy, but the emperor disagreed and all must obey the emperor.


Serpents’ heads that once guarded the staircases leading up to the shrines at the top of the Templo Mayor.

In an alcove carved out behind one of the staircases, there was a stone medallion depicting the dismembered body of a woman. The woman was Coyolxauhqui, the older sister of Huitzilopochtli. According to the myth, Coyolxauhqui became angry when she learned that her mother would have a baby, so she allied with her hundreds of brothers and sisters and plotted to kill both mother and child. Huitzilopochtli heard this plan from his mother’s womb, so he made himself emerge a full-grown warrior and killed his sister. Then he chopped her body up and threw her pieces down a hillside.


The oldest remains of the Templo Mayor. For centuries is was encased in several layers of stone facades, but now it breathes air again and is in pristine condition.

For the ancient Egyptians, pyramids were meant for burial, but for the Aztec, pyramids were stages — platforms raised high above the plaza so spectators could gather and see the rituals being performed at the top. On the Templo Mayor, in front of the shrine of Huitzilopochtli, it is believed priests would reenact the story of Coyolxauhqui by decapitating prisoners and rolling their bodies down the steps of the pyramid. The bodies would come to rest near the medallion depicting the goddess whose story their sacrifice symbolized.


The medallion depicting Coyolxauhqui, after she was dismembered by her brother.

But why was the medallion behind the staircase? Over time, the Aztec kings added onto the temple as a show of their success and of their devotion to the gods. They would build a new shell right over the old pyramid. With the top gone, now the structure looks a bit like those Russian nesting dolls, with one facade, one staircase and one medallion behind another. There are seven layers of facades, and inside those, in the center of the structure, is the very first temple, magnificently preserved. It’s a stunted-looking pyramid from the early days of the city.


Two of the Templo’s old facades, one inside the other.

Near the temple, a few other structures are preserved, including the House of Eagles, where members of the order of Eagle Warriors would gather for rituals, some of which involved human sacrifice. There are beautiful stone benches lining the walls, whose intricate relief images still bear their original paint. Archaeologists have found traces of what could be blood on these benches. It has been argued that auto-sacrifice was practiced there. Men would sit and let their own blood as a sign of devotion to their gods.


A stone bench lining the wall of the house of eagles, still with its original paint.

Obviously, there was a lot of violence and bloodshed within the Aztec Empire. Human sacrifices usually would have been prisoners of war. The Aztec were known to start “flower wars” in which they would engage another city in combat for the sole purpose of capturing warriors for sacrifice. In order to become an Eagle Warrior, one had to capture a certain number of prisoners in two consecutive battles. The capture of prisoners was believed to be vital to the future of the kingdom. The Aztec gods required blood. For them, blood was kind of like Gatorade; it gave them energy do perform the celestial duties. Without blood, the sun would not rise, the winds would not blow and life would end. Within the remaining walls of the Templo Mayor, archaeologists have found sacrificial victims from other cultures around Mexico, buried with objects related to their society. These burial caches were meant to symbolize that Huitzilopochtli, the most important Aztec god, held dominion over all the peoples of Mexico. This brutal practice was one of the reasons that Cortéz was able to gather a massive army of indigenous warriors with which to fight the Aztec. The empire had made many enemies.

But besides all the violence and bloodshed, the Aztec were a highly innovative society. The air is rather dry in Central Mexico, and for that reason Lake Texcoco, the lake in which the Island City of Tenochtitlan was built, was a salt lake. However, the Aztec were able to create areas of freshwater by building dams between the areas where freshwater was coming down from the mountains and the briny water in the rest of the lake. Also related to the importance of water is the fact that the Valley of Mexico was filled with many cities and cultures at the time, and there was a fair amount of competition for arable land.

One of the ways the Aztec helped solve the need for more land was to build chinampas, basically islands of rich soil dredged from the bottom of the lake. These man-made islands huddled around the margins of Tenochtitlan and hugged the shores around Lake Texcoco. They created their own farmland. Of course, another way they fixed the problem was to conquer the territory of surrounding cultures.

The Spanish were in such awe of the achievements of the Aztec that they named their new city after the leading tribe among the Aztec people, the Mexica. The seal of Mexico is taken from the Mexica legend of how they settled on the island. The story says that Huitzilopotchli had told the holy men of the Mexica to look for an eagle perched atop a cactus, eating a snake. That would be the sign that they had arrived at their promised land.


In the Historic District, a dilapidated colonial exterior enshrines , of all things, a McDonald’s, along with other modern stores.

Now, the island is gone. It was drained by the Spanish, who did not understand the purpose of the dams. Now most of Mexico City lies at the bottom of the valley, which was once underwater. Flooding is a big problem.  I still remember the last night we were in Mexico City. We had been enjoying the Museum of Anthropology all day, and in the evening (as had happened every evening we were there) the moisture that had evaporated in the dry sunlight all day and had been trapped by the mountains began to rain down as the air cooled. It was a hard rain and we couldn’t get a taxi, so we were forced to brave the torrent. And it was truly a torrent. The rain beat down from the sky and washed into the streets, flooding as deep as a foot in places. There was a point when we had to climb onto the high stone base of a wrought iron fence and scoot along, holding onto the bars to avoid slipping up to our knees into the deep water in the streets. There was a whole crowd, young and old, scooting along with us.


Fernanda trying to stay dry during a flood downtown, which are quite common.

In spite of the rain, it was a wonderful trip, and sometimes I go up to the John P. McGovern Hall of the Americas on the third floor to stand in the re-creation we have of the Templo Mayor and spark memories from the trip. I hope you will come and visit too. Our re-creation is scaled down, but at the top of the structure we have an actual statue of a god related to Quetzalcoatl and objects from different cities cached in our walls, much like in the original. Some of the objects are beautiful (but dangerous) obsidian blades that were actually used by the Aztec, most likely in rituals of burial.

We also have some mummy masks and incense burners for the mysterious city of Teotihuacan, a city so old and so impressive the Aztec believed it was built by the gods. They considered it a holy site, and its history is worthy of a blog of its own. When I stand in our little ruined pyramid, all by myself, visions of the white sun come to mind. I remember the dry breeze blowing across the valley and the sound of indigenous flutes being played, albeit by street vendors who always hounded me to buy their stuff. Still, the music they made in attempt to lure tourists and their cash lent a mystical air to the site which I really appreciated. So if you’re planning a trip, come get inspired like I do. In the Houston Museum of Natural Science, we have many pieces on display and all of them have a cool story and a place of origin. Maybe you will discover a new destination.

Editor’s Note: “Cretaceous” Chris Wells is a Discovery Guide at the Houston Museum of Natural Science.

Celebrating Excellence In Science and Math: the Wilhelmina C. Robertson Teaching Award

Through the generosity of the Cockrell Foundation, The Houston Museum of Natural Science is proud to offer the Evelyn Frensley Scholarship for Outstanding Achievement in Science or Mathematics.

The deadline for the 2015 Teacher Award has been extended until Friday, September 18, 2015.   

In recognition of the fine educators of Houston, we also offer the Wilhelmina C. Robertson Excellence in Science or Mathematics Teaching Award. This award of $2,000 will go to one K-5th grade science or math teacher, and one 6th-12th grade science or math teacher who demonstrates significant ability and dedication to teaching in either discipline in Harris County.

You may nominate an outstanding teacher by filling out the 2015 Teaching Award Form.

The deadline for all submissions is September 18, 2015.


Houston Museum of Natural Science President Joel Bartsch appears with attendees of last year’s Wilhelmina C. Robertson Excellence in Science or Mathematics Teaching Award Luncheon and the 2014 winners. Nominations are still open for this year’s award. Pictured from left to right are Rebecca Grekin, Rachel Shenoi, winners Erin Meyers and Nancy Brock, and Dr. Bonnie J. Dunbar.

2014 Educator Awards

Last year’s Wilhelmina C. Robertson Excellence in Science or Mathematics Teaching Awards and scholarships were presented to Erin Meyers of Cypress Lakes High School and Nancy Brock of Oyster Creek Elementary School at a special luncheon held at The Junior League of Houston on October 21. The recipients and guests at the luncheon were treated to keynote speaker Dr. Bonnie J. Dunbar, astronaut, accomplished engineer, and science educator.

For questions or more information.


Stego says HMNS makes field trips easier on teachers

by Kaylee Gund

Hi all,

Stego the Stegosaurus here, putting my best plate forward for the beginning of the school year!


Stego the Stegosaurus, team leader for the field trips department.

I was chatting with my Discovery Guide pals the other day and we’re all looking forward to the great school field trips we see every year. But surprisingly, a few local teachers they’ve spoken to are intimidated by the prospect of planning a field trip.

I have to admit, the idea of taking more than 500 students off campus and bringing them back in one piece does sound overwhelming, but here at HMNS, it’s our job to make field trips the best possible experience for everyone involved.

As the face of the Youth Education Sales team, I, Stego the Stegosaurus, feel duty-bound to dispel the myth that organizing a field trip is by nature stressful. In fact, I’d like to take this opportunity to introduce you to two wonderful ladies who can give you all sorts of great tips and ideas for students to put a spike in their learning curve (pun intended).

Karly - Paleo

Karly Hunt, Marketing Coordinator (khunt@hmns.org).

The newest member of our team, Karly Hunt, is the Marketing Coordinator for all districts west of Houston. She comes to us from Liberty Hill ISD, where she taught high school science. Karly, by the way, appreciates a good chemistry joke, but unfortunately all the good ones Argon… Get it?

This is Karly’s first year at HMNS, but she is already hard at work sharing her love of all things scientific with Houston educators. Her favorite part of the museum is the Morian Hall of Paleontology.

“We have such an amazing collection that really puts prehistory in perspective,” Karly said.

Needless to say, being a dinosaur myself, I like her already!

When she’s not traveling to schools, you’ll find Karly spending time outside, enjoying music of all genres, and playing with her dogs.

Cathy - Jurrasic Bark

Cathy Walton, Lead Marketing Coordinator (cwalton@hmns.org).

Cathy Walton, our Lead Marketing Coordinator, is the museum representative for schools in Houston ISD, districts centrally located in the metroplex, and districts to the East. Having originally taught World Geography in Tennessee, she began her career at HMNS three years ago. Cathy is a wizard at finding field trip packages that fit an individual teacher’s needs, and she loves being able to work with amazing educators to help them inspire their students. She encourages teachers to “be as creative as you can to get students excited about learning!”

Cathy enjoys hiking, cooking, and entertaining (when she’s not hanging out with us dinos, of course). Fun fact: she grew up in Shelbyville, Tenn., better known as “Pencil City,” home of the No. 2 pencil!

If you have any questions or would like to know what exciting new exhibits your students can learn from next, feel free to contact one of these representatives. Check out our free curriculum and our field trip preparation guide for more info, too. And you can fill out a booking request form online if you already have an idea of what you’d like to do at the museum.

Have fun, keep learning, and we’ll see you soon!




Editor’s Note: Kaylee Gund is in Youth Education Sales at the Houston Museum of Natural Science.