The Truth is in the Tooth

When you take a bite into a juicy hamburger or dive into a pile of asparagus, do you ever wonder how you’re able to eat the way you do? Humans, by nature, are omnivores; this means that we eat fruits, veggies, and various meats. If you NEVER saw a person eat, though, you could still tell what his diet was! The truth is in the tooth, my friend.

something will jump in my mouth, if i just wait long enough
Creative Commons License photo credit: PhyrePh0X

Canine teeth (you could call them your vampire teeth) are found in carnivores, or animals that eat meat.  For instance, you wouldn’t find any blunted teeth in the mouth of a Velociraptor! Molars, on the other hand, are used by herbivores (animals that eat plants) for grinding hard to digest foods. Try looking into the mouth of camel sometime and see what you find – watch out though, they spit.

Diphyodont animals, like mammals, have two sets of teeth in their lifetime.
Polyphyodont animals like sharks have teeth that are constantly being lost and replaced; they grow a new set every few weeks. Can you imagine losing every tooth in your mouth twice a month? Sounds pretty terrible, but at least you’d collect a lot of quarters under your pillow! Incidentally, the Shark Tooth Fairy is also the Queen of England.

Elephant Tongue
Creative Commons License photo credit: greggoconnell

Another useful tool for eating is the ever-important tongue. Some tongues are attached and cannot be stuck out, like the elephant (no raspberries there,) and some are used for more than just eating. Cats’ tongues are rough to aid in grooming, for instance. A frog’s tongue is sticky to trap their food and bring it to their mouths. Did you know a frog uses its eyes to swallow? If they used their tongues, they’d choke.

If you find yourself without the opportunity to observe the mouths and eating habits of wild and extinct animals, come on down to the Museum! It’s the only place in town where you can see a poison dart frog in action and view a T. rex locked in battle with a duck-billed dinosaur.

Ghosts in the Trees

Last night, I was reminded of how unusual some of the insects we raise here in the Cockrell Butterfly Center are to most people. I had set up a table in the grand hallway of the museum to promote our outreach program, cleverly titled “Bugs on Wheels.” As soon as I left the Butterfly Center’s doors, I had drawn a crowd that didn’t seem to subside for the entire evening!

I think what grabs most people’s attention are our exotic walking sticks, which we have been displaying for several years. As soon as people see our giant prickly stick, they commence with “what on earth is that?” type of comments, and I love to educate them!

Walking sticks belong to the insect order Phasmatodea or Phasmida. This name comes from the Latin word phasma, which means ghost. It refers to their amazing camouflage skills, which in the right setting, can make them vanish right before your eyes! These insects are all herbivorous and harmless, having no venom or large mandibles for biting. This makes them an easy target for insectivores! So they have come up with some pretty fantastic ways to protect themselves from predators. These insects have simple metamorphosis, so the immature nymphs, look like tiny versions of the adult. Here at the butterfly center, we raise 5 different species of exotic walking sticks. I’d like to share a little about each one with y’all!

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Creative Commons License photo credit: emills1 
an immature female

The Giant Prickly Stick, or Extatasoma tiaratum, is one that really draws the crowds! The females are very large, 6 to 8 inches in length, and very fat! They range in color from light peach to dark red-orange. They are often – almost all the time, actually – mistaken for a scorpion. This is no accident, this species is native to Australia, the venom-capital of the world! They spend their entire lifetime hanging in eucalyptus trees feeding on the yummy foliage and easily folding themselves to resemble a dried up leaf.

If they are spotted by a potential predator, they will curl their abdomen to look remarkably like a scorpion. This warns predators that if they don’t want a nasty sting, they should stay far away. What a clever defense! Since they are, of course, completely harmless. They have a very soft exoskeleton which keeps them confined to the safety of the tree tops. If they need to do anything like lay an egg, they drop it to the leaf-covered ground. The females have small vestigial wings, but are incapable of flight. They can lay up to 1,000 eggs in their lifetime and can live a little over a year. The males are quite a bit smaller, very thin, and excellent fliers. They are equipped with much longer antennae than the female, which they use to sniff out a mate.

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Creative Commons License photo credit: emills1
Spiny Devil

The Spiny Devil (Eurycantha calcarata), is a close neighbor of the prickly stick; they are native to New Guinea. These adorable stick insects have very different habits. They are equipped with a very hard exoskeleton that is covered in hard spines, especially the legs! Since they are a harder egg to crack, they are not as attractive to eager insect-eaters, plus, they put up quite a fight! They can use their legs as a weapon by squeezing with all of their strength. I can speak from experience and say, it hurts!

When threatened, they can put on quite a show, raising their abdomen and back legs. We like to call it “the handstand of pain!” Since the female has the freedom of reaching the ground, she uses the pointy tip of her abdomen (her ovipositor) to lay her eggs deep in the soil. The male and female look quite similar, both are wingless and they are nearly equal in size. Both sexes can live for about a year and a half as adults – not bad! The male does have one distinguishing characteristic, a single very large spine on his hind femur.

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Creative Commons License photo credit:
emills1 Ouch!

They are very territorial and use this spine for fighting. They can seriously injure or even kill another male during combat. Still want to mess with these guys? Well, the males can also emit a very foul chemical that smells just like a skunk. However, they are usually pretty laid back.

The Phyllium celebicum or moving leaf insect is a breath of fresh air. These leaf mimics are petite, dainty, have no spines or smells, and are 100 percent cute! They inhabit the rain forests of Malaysia.

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Creative Commons License photo credit: emills1

Since they have no other defense mechanisms, their camouflage has to be absolutely perfect, and well, see for yourself! They also spend their entire lives in the canopy, dropping their eggs to the ground haphazardly. The female, pictured right, has larger wings than the Giant Prickly Stick, but their only function is camouflage. The male is half the size of the female and he’s an amazing flyer! These live a little under a year and we love to have them around.

I actually noticed something very interesting from observing them. The outer 1/2 inch of the female’s body is only a layer of skin, and all of the organs are arranged down the very middle of the abdomen. This is important because I started seeing a couple of them missing chunks of their abdomen, but they didn’t appear to be injured. I’m sure they get nibbled on by several herbivores in the wild – it’s a pretty cool adaptation.

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Creative Commons License photo credit: emills1

Sharing the same rain forest is the Giant Jungle Nymph (Heteropteryx dilatata). They are spectacular, very large and beautiful. The females are bright green and usually 7 inches in length with a wide abdomen. They have small wings which they rub against their bodies to produce a hissing noise. Their thorax, abdomen, and legs have rows of sharp spines. When disturbed they thrash around violently and they also do “the handstand of pain.”

They spend most of their time in the trees and only travel to the ground to lay their eggs. The male is brown and only about 4 inches long. They have bright crimson hind wings and are very showy. They are always very nervous and thrash around a lot! This species is harder than the others to raise. They need high humidity and they take a long time to develop.

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Creative Commons License photo credit: emills1
a male

The eggs take around 17 months to hatch and the nymphs take over a year to develop into adults. This species can be very aggressive, but we always end up with a few that can be handled, they are very curious and active. 

The last resident of southeast Asia is the Annam stick insect (Baculum extradentatum). These look very similar to our native walking sticks. They are very slender and really resemble a twig. These are interesting little creatures. When disturbed, they will essentially go limp and flop to the ground. It’s really the only option for them since they are so defenseless.

The most interesting thing about this species is that they can be completely parthenogenic. This means that the females can reproduce without males. We do have males in our populations and it is a full time job making sure we don’t have too many individuals. They are egg-laying machines. Their life span is about a year and males and females look very similar, but the males are much smaller.

These walking sticks are some of the most amazing insects I’ve worked with. I’m so impressed with their diversity and beauty. Next time you see them in the Entomology Hall or in the Grand Hall, come by and see them, you’ll certainly be amazed!

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Creative Commons License photo credit: emills1
male
Baculum





Draw Dinos Right!

Someone asked me: What are you?  Science Guy or Artist?

Both.

Leonardo da Vinci said: “I don’t understand a thing ‘till I draw it.” When you draw, your finger tips teach your brain what’s important.

Cleaning Bones & Feeling Dinosaur Muscles

Most fossil-cleaners are good artists.  As they chip away the rock, their finger tips record each bump and hole, every place that’s smooth, every place that’s rough. Expert fossil-cleaners dream about the fossil – they see it rotating, turning every which way.

Let’s say we have an ankylosaur skeleton, fresh from the field. We clean off the rock slowly. Every time we have a square inch clean, we paint thin glue on it (so it doesn’t crack and fall apart). As we do, we make sketches of the bone. That helps plan the complete cleaning. It’s X-ray vision, sort of.  As we sketch the bone we can draw in the parts of the specimen that are still buried in the rock.

For instance: let’s say we have the upper left arm (humerus). And we have the elbow end cleaned, but the shoulder end is still in the rock. A sketch will help us imagine where the bone is and how to chip the rock off so we don’t break anything accidentally.

Putting Muscles and Ligaments Back On

Fossils from a Dimetrodon hip bone.

Texture of fossil bone is important:

Rough spots full of squiggly ridges are where tough ligaments and tendons attached to the bone.

Smooth spots are where soft muscle attached.

Bones with big pits are armor plate – in life the pits were filled with a thick layer of finger-nail like skin.

At the Zoo with Brachylophosaurus

Now let’s shift to Leonardo, the Brachylophosaurus,  the dino-mummy now visiting the Houston Museum of Natural Science. I wanted some drawings of the critter, and to prepare I spent a lot of time watching live animals.

I sketch live critters in the zoo all the time.  And I make diagrams of the heads, bodies and legs of skeletons from species that are still alive today. I can’t imagine a live Brachylophosaurus  or any other dinosaur without studying rhinos and elephants,  ostriches and cassowaries, giant tortoises and water buffalo.

Tweensy Gator Hands

Most plant-eating dinos have hands like the one in the little vegetarian dinosaur Hypsilophodon.  There were five fingers in this animal and most other herbivores. Carnivores sometimes have  three, as in Velociraptor,  or two as in T. rex  and all members of the rex family.  In all dinos, meat-eater and plant-eater,  only the inner three fingers had claws. In herbivores the claws are blunt and hoof-like. Carnivores tend to have sharp-tipped claws. In all dinos, the outer two fingers had no claws at all.

The five fingers/three claws is standard equipment for most ancestors of dinos too.

Gator
Creative Commons License photo credit: James Jordan

Who has this  five/three  hand in a zoo today?  Only in one clan – gators and crocs. Lizards and turtles have claws on all five fingers.  Crocs & gators have three claws, five fingers, no claw on outer two. Watch out when you draw dino hands – a lot of books make the mistake of giving a dino  four or five claws. Even the movie “Jurassic Park” makes that error with the Triceratops. Don’t YOU do it! Remember: five fingers but only three claws in most plant-eating dinosaurs.




No Bowling for Duck-Bills

Duck-bill dinos have a puzzling variation on the basic veggie-saur hand. The outer two fingers are fine – no claw or hoof. But there are only four fingers in total. Which is missing? The thumb. Duck-bills are the only dinos without any thumb. That’s strange because the thumb is usually one of the strongest fingers in all other dinosaurs. Even T. rex  has a thumb. There’s a predatory dino with just one finger – Mononychus – and that single finger is, you guessed it, the thumb.

One result of being thumb-less is that when you’re choosing a bowling team, you don’t want a duck-bill. They can’t hold the ball. Continue reading