Being Natural: Tina Petway

When Tina Petway, Associate Curator of Malacology, retired as a schoolteacher in 1999, she finally embarked on fulfilling her dream since she was 12 years old.

Growing up, Petway was frustrated by the lack of resources for young women interested in scientific careers.

“I was walking on the beach, and I ran into this lady who was picking up shells,” Petway said. “She invited me to come back to her house and her office. She gave me shells, Texas-collected shells. Absolutely brilliant lady.”

This lady was none other than Mildred Tate, a renowned malacologist who helped found the Brazosport Center for the Arts and Sciences in Clute, Texas. Tate gave Petway rare specimens, many books, and a strong foundation for future adventures.


Associate Curator of Malacology Tina Petway pursued shell science later in life. Now she’s an asset to the Houston Museum of Natural Science’s malacology program, and she is full of stories.

Though Petway loved teaching, her passion was malacology. She had a brief stint as an interior decorator right after she finished school but then realized just how precious her shells were to her. The walls of model homes were too static for her, so Petway added some shells and coral specimens from her personal collection to liven things up.

“Well that went over really well and people wanted to buy them. I didn’t want to part with what I had! So that didn’t last too long,” Petway said.

She joined the Houston Shell Club (now the Houston Conchology Society) when she was 16 years old and never looked back. Soon, she was dragging her husband around all over the world looking for rare and exotic specimens. The couple met by coincidence near a family member’s bayhouse, and Petway knew they would get married after just a few months.

“I said, ‘I collect and buy seashells. I go places where there are shells, land snails, freshwater mollusks. That is my scope for life. If I take a vacation, it’s going to be some place like that. And I will continue to buy shells with money I earn. If that’s not ok, if you can’t deal with that, then let’s just be friends and forget this,’” Petway said. “And he said, ‘You know, if you can’t beat them, you join them.’ So he started buying shells, too! He’s as big a collector as I am.”

The pair were together on an uninhabited island in the Solomon Islands chain in 1972 when Petway had an encounter with a venomous cone snail, a group of gastropods that Petway says is her favorite family of mollusks. These snails are carnivores that use venomous barbs loaded with a cocktail of neurotoxins to kill prey. Even today, there is no antivenin. According to Petway, the way to survive is to load up on antihistamines so you keep breathing and use meat tenderizer to draw out the venom.


Petway discusses the anatomy of an octopus and other cephalopods in the Strake Hall of Malacology.

Petway was collecting specimens in small jars when she saw a cone snail scurrying along the reef. Recognizing it as venomous, she picked it up from the base with her right hand, pointing the aperture and barb down and away from her hand as she maneuvered to get a jar and open it.

At that time, another cone snail appeared, and Petway couldn’t resist. She transferred the snail to her other hand, picked up the new specimen and put it in the jar. At around that time, she felt a shooting pain in her left hand.

Petway looked at her left hand and saw that the cone snail had emerged, swung around and stung her on her pointer finger three times. She was 30 miles from the nearest airplane, three miles from the nearest habited island, and too far away for modern medicine to help. Of course, the first thing she did was put the snail in the jar for safe keeping; she still has it to this day.

“I thought, ‘Whoa, I don’t feel good.’ My head was hurting, my eyes were starting to get fuzzy, I was having a hard time breathing, my heart was pounding, and it was then that I accepted that, ‘Dang it, I’ve been stung!’” Petway said.

She hurried to the shore, took lots of antihistamines, wrapped meat tenderizer in a papaya leaf around her finger, and laid down. At that point, she was having difficulty walking, things were blurry, and her breathing was labored.

Petway thought, “‘Well if this is it, I went a really cool way.” What else can you say at a time like that?

The next day, the headache was still there, but her vision had cleared. The headache would remain for about a month, and it was over 10 years before Petway regained full use of her pointer finger.


Petway explains the features of the Australian trumpet shell, the single largest shell in the world and the crown jewel of the Strake Hall of Malacology. Petway estimates that the snail who made the shell was more than 100 years old.

Petway began volunteering at the Houston Museum of Natural Science in 1999 when John Wise was the curator of the Strake Hall of Malacology. When Wise left in 2005, Vice President of Collections Lisa Rebori asked Petway if she could fill in for a while.

“I said sure, of course! At that point, I had been through the whole collection and had pretty much self-cataloged everything that we had and had even started rearranging,” Petway said. “I just kind of started one day a week helping out, and I’ve been here ever since, and you can’t run me off.

“I eat and sleep this job. I absolutely love what I do. I love coming into the museum every day.”

Petway has led the way in a massive undertaking to revamp the Strake Hall of Malacology. Already known around the world as the premier collection of shells, HMNS has over 2.5 million specimens in storage and is working on purchasing more. The new hall will feature more rare specimens and more educational information about mollusks and their habitats.

“There is so much to learn about these animals, and that’s what we want to teach in this new hall. They’re not just pretty, and they are beautiful, but the animals that makes the shells are even more beautiful,” Petway said.

Petway is very passionate about conservation efforts for the world’s oceans and is a strong believer that education is a great method to promote the importance of these habitats. She is hopeful that the new hall will help convey that message to future generations.

It’s something she’s been seeing her whole life.

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Holiday How-to: Chocolate Leaves

My mom was a chemistry and home-ec teacher, so I grew up in a home where ingredients were carefully measured and food items were attractively arranged. While I got to help out in the kitchen as much as I wanted, I always liked being in the kitchen around the holidays. There were always new tricks or special touches added to dishes and along with these came short science lessons on why we were doing things that particular way.

One of my favorite things to help with in the kitchen were chocolate leaves. When done correctly, these are perfect little molds of the living leaf, just like the perfect molds and casts in the Morian Hall of Paleontology.

A chocolate leaf is made by smearing melted chocolate onto a leaf and putting it into the fridge to harden. Sounds easy, right? It is pretty easy. Read on!


Activity: Chocolate Leaves


Leaves (*See note in step 1.)

Chocolate candy melts

Parchment or wax paper

A cookie sheet or plate for your leaves to rest on as they cool


1. Pick your leaves. I like to use slightly waxy leaves so you don’t have to worry about fuzzy bits in your chocolate. NOTE: Learn about the plant you are picking leaves from before you decide to use them. Many household plants are decorative but poisonous.  Oleander is a great example of a plant that is pretty but poisonous. If you hate botany or don’t know about the Internet, getting pre-packaged basil or mint from the grocery store is a safe way to go. These leaves will be a little less firm, so you will need to be more careful with them.

2. Don’t pick leaves from poisonous plants. Seriously.

3. Wash your leaves with soap and water, rinse them thoroughly and then dry them completely. The chocolate won’t stick to wet leaves, so don’t rush this step. You will only be frustrated.

4. Put wax or parchment paper on a cookie sheet or plate. You want this to be something that will fit in the fridge with no problems.

5. Get out your candy melts. The melts come in a hundred colors. We are using chocolate colored ones in this tutorial. There will be instructions on the package on how to melt the specific brand of melts you purchased. In general, you will put the melts in a microwave safe bowl and microwave them a few seconds at a time stirring as you go. Don’t overheat the melts. They get gross and there is no coming back from that.

6. When you have everything melted and creamy, hold the leaf by its stem. I like pinching it between my thumb and index finger and then using my middle and ring finger to support the leaf. Do what feels comfortable to you.

7. Dip your stirring spoon into the chocolate. Use the BACK of the spoon to spread the chocolate on the leaf. Make sure the chocolate is thick enough that it won’t break when you try to peel it. Place the leaves on the parchment as you work, and don’t let them touch.


8. The side of the leaf you use is up to you. If you are using mint and you put the chocolate on the back of the leaf, you will have some crazy patterns.  If you want something more subtle, use the front of the leaf. Coat the leaf almost to the edges. If you go too far, you will get ugly edges that are hard to peel. But don’t worry! Those leaves are the best to eat.

9. Put the tray of leaves in the fridge and wait a few minutes.


10. When the chocolate is set, peel the leave off the chocolate. You should have a perfect little mold of your original leaf. This may take a little practice. Work quickly as you have something designed to melt with heat in your hot little hands.

11. Done! You can store the leaves in the fridge until you are ready to use them. If the leaves got soft when you were working with them, put them back in the fridge to firm them up. Once they are firm, you can toss them in a plastic container.


Okay! So what’s the science here?

The word “chocolate” comes from the Nahuatl word Xocolatl for “bitter water,” referring to its original incarnation as a hot, spiced beverage in the Mayan and Aztec traditions. Traditionally, chocolate is a mixture of cacao powder, cocoa butter, and a sweetener. To make chocolate palatable and stable, we now mix milk solids, added flavors, modifiers, and preservatives.

Those candy melts? NOT CHOCOLATE! In this example, they are sort of chocolate colored, so they have that going for them, but they also come in a bunch of colors that are not known to nature so… not chocolate. They are mostly made of sugar and vegetable fats – not cocoa butter – and depending on the brand, they may throw in a little wax for better melting. Mmmmm… wax.

The advantage to the melts over the regular chocolate is that they do have the wax and the vegetable oil in them, which makes melting easier since the chocolate doesn’t need to be tempered. It hardens pretty quickly and sticks to whatever you dip in it, so it makes a great coating for cake pops or whatever crazy things show up on Pinterest this month.

Want to get super nerdy about your chocolate?  (I assume you do…) MIT has these tidbits available.

What’s in typical chocolate?

  • 10-20% cacao
  • 8-16% milk solids
  • 32-60% sugar
  • 10-20% cocoa butter
  • 2% theobromine and polyphenols

Cocoa Butter Chemistry

Fats and oils are organic molecules made up of three fatty acids chemically linked by an ester bond to glycerol. Fats are solid at room temperature, while oils are liquid.

Cocoa butter fats are made up predominantly by three major fatty acid molecules: Palmitic Acid, Stearic acid, and Oleic acid.

Oleic acid is unsaturated (has a double bond on its carbon chain), making it kinked and unable to pack well with other molecules. Because of this, a greater portion of oleic acid in the fat results in a lower melting temperature for the cocoa butter.

Chocolate makers can adjust the amounts of each fatty acid to produce a chocolate that melts only in the mouth, giving it a superior quality.

Tempering chocolate

The cocoa butter in chocolate can have several different crystal structures (three-dimensional patterns in which the fat molecules pack). There are six known chocolate crystal forms, or polymorphs. You can obtain each form by varying the fatty acid ratios and the temperature at which the chocolate is tempered (cooled).

Only a few of the polymorphs are considered good for gourmet chocolate because they give the right blend of snap (when you bite into the chocolate) and melting (when it warms up in your mouth). Melting is especially important because it controls how well the chocolate disperses and releases flavor onto your tongue.

Whether you will be constructing culinary masterpieces this fall or sitting back and enjoying the kitchen creations of others, we hope you have a happy holiday with you and yours!  (And when you’ve had a little too much togetherness, we will be open on Friday…)

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Light Up Your Holiday at Jingle Tree in Sugar Land!

Through the doors of the Houston Museum of Natural Science at Sugar Land, you usually see the towering display of a Tyrannosaurus rex. But these past few weeks, that sight has been amplified in the twinkling light of custom-decorated holiday trees.


When you walk through the front door of HMNS-SL, trees now surround the T. rex display.

The collection of trees are ready to go to the highest bidder through the museum’s Jingle Tree program, an annual online and live auction fundraiser that benefits the museum. From frilly to sparkly, these trees are a fascinating display of the creativity of the Fort Bend designers, volunteers and artistic visionaries who made them. Some even include wild themes that push the look of the traditional holiday tree to the limits. Check these out!


Trees with a traditional look offer a lineup of the best in ribbons and ornaments. It’s like a fashion show for tannenbaums!


Here’s a close-up of the white-and-silver accents on Diamonds Are a Girl’s Best Friend!


Santa’s mischievous helpers are playing at the top of Elves Made Me Do It.



Wonderful hand-made paper roses and pinwheels in Flower Power!


This tribute to the natural world called Enchanted Forest comes with wood accents and, yes, antlers!

Now get an eyeful of these non-traditional looks.


Sleepy crescent moons make this tree, Love You to the Moon and Back a celestial beauty.


This tree, named SEAson’s Greetings, looks like it went snorkeling and brought back some friends!


Take a close look at this Star Wars tree. Yes, those are lightsabers, and yes, that’s Darth Vader at the top!


This tree, named Noelle, is the belle of the ball, showing off its fashion sense.


And finally, nothing says HMNS like dinosaurs! Plastic toys large and small cling to the branches in Dinotopia.

There’s many more where that came from, and you can see them all at the third and final tree-viewing event, the Jingle Tree Happy Hour. Come out Thursday, Nov. 19 from 5:30 to 8:30 p.m. to have some cocktails and bid on trees and other items in a live auction. Don’t miss the opportunity to take one of these gorgeous pre-decorated trees home for the holidays!

Editor’s Note: All photos by Kelly Russo.


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Mark Your Calendars for these events happening at HMNS 11/16-11/22

Bust out your planners, calendars, and PDAs (if you are throwback like that), it’s time to mark your calendars for the HMNS events of this week! 

Jingle Tree 3

Film Screening – The Northern Lights: Nature’s Spectacle with Pal Brekke
Monday, Nov. 16
7:00 p.m.
Imagine what it must have been like for the first northern inhabitants to raise their eyes to the dazzle of the Northern Lights. The Aurora Borealis still casts its mysterious and colorful spell over us, and Norwegian solar physicist Dr. Pal Brekke has captured that enduring fascination in a new documentary, The Northern Lights: A Magic Experience.

Sip ‘n See Open House & Luncheon
Tuesday, Nov 17. 
11:30 a.m. – 1:30 p.m.
HMNS at Sugar Land
Next up is our open house Sip n See, Tuesday, November 17, from 11:30 am to 1:30 pm. This fabulous strolling lunch event will allow you, your friends and associates to see the trees up close and perhaps even “pre-buy” the one you fall in love with!

Lecture – Fire Masters: Cooking and Feasting 10,000 Years Ago by Andrew McCarthy
Tuesday, Nov. 17
6:30 p.m.
The food we eat and its preparation define us as humans as few things do. Archaeologists theorize that cooking and feasting enabled the human brain to expand. Excavations on Cyprus reveal the presence of large stone ovens much larger than a single tribe required, apparently for the purpose of sharing feasts in the Neolithic period dating to 10,000 years ago. Dr. Andrew McCarthy will explore how cooking and feasting may be decisive steps toward the development of civilization. Perhaps the origin of our holiday feasts is result of humankind³ greatest prehistoric inventions.

Drink and be Merry Happy Hour and Auction Closing
Thursday, Nov. 19
5:30 – 8:30 p.m.
HMNS at Sugar Land
We’ll wrap things up with a cool Happy Hour, Thursday, November 19, an evening filled with cocktails, tree viewing, on-line bidding and a fabulous live auction. All bids close that evening at 8:00 pm!

Class – Atlatl Workshop: Stone Age Spear Slinging
Saturday, Nov. 21
9:00 a.m.
Journey into prehistory by literally chucking the past! Experimental archaeologist Dr. August Costa will introduce you to the science and prehistory of hand-cast projectiles and biomechanics of their use. Participants will build their own cane dart and learn how construct throwers. After instruction on using the Stone Age spear-throwe–the atlatl, participants will fling full-scale replicas at stationary targets. The class will culminate in a tournament competition, with a sharp grand prize.

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