Why is That Cage So Dirty??

If you look at some of the arthropod cages in the Insect Village, you might think that Animal Care is not very good at keeping the enclosures clean. Actually something else is going on that’s necessary in taking care of our animals.

Some of the terrariums, especially the ones that contain a whole colony of cockroaches, have a stripe of a grimy looking white film on them. That is a substance called Fluon®, a synthetic fluoropolymer that is used for a variety of applications. So why do we paint it on our cages? Because some insects have very sticky feet!

Fluon® acts as a slippery lubricant barrier between the insect habitat at the bottom of the cage and the lid at the top. Animals like our Madagascar Hissing Cockroaches can actually climb the smooth plexiglass walls of our cages and are only foiled by that slippery band of Fluon® that surrounds the cage.

When taking care of a colony of insects, containment is always a main concern. We want to know where our animals are at all times. And thanks to Fluon®, we can reliably know that these insects are staying at home.


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Cockroach Spit

Caution: The following article is about whether cockroaches are spitting or vomiting. You may wish to proceed with caution.

If you have ever visited Pacific Science Center’s Insect Village, you may have had an opportunity to handle a Madagascar Hissing Cockroach (Gromphadorhina portentosa). Many people have learned a new appreciation for insects from this contact. Some have overcome longstanding fear of bugs. But few know that the cockroaches have to learn not to fear us, too.



While many legends exist about the ability of cockroaches to survive nuclear disaster, microwave ovens, and other dire fates, the experience of our Life Sciences staff has been that these insects are not invulnerable. They enjoy being treated well and show signs of stress when times get tough, just like any other animal.


Roaches show stress in several ways. Most commonly they hiss (hence their common name) the first few times we handle them, before learning we are safe. We also look for loss of muscle tone, and fighting as signs that the animals need more rest and less work.

But there is another sign of stress that has been observed recently, that got us concerned. A couple of people have seen our roaches emitting bubbles of clear liquid from their mouths during handling. Life Sciences manager Sarah Moore had seen this behavior before. It happened once while treating the roaches for mites, something they really hate. It occasionally happens when a roach is accidentally dropped, or when brand new animals are introduced. But it has been uncommon, and when it happens it is of note.


The usual modes of inquiry turned up very little information about this phenomenon, but we did learn this: The liquid is not vomit, but saliva, which roaches produce in large amounts to help mobilize and digest food. German and American roaches are known to use pheromones in their saliva to attract others of their species and also to communicate danger. Depending on the pheromone, other roaches will either approach or flee from this secretion. It is possible that our roaches are doing the same thing.

At any rate, it was clear that the insect doing this was unhappy, and he was moved out of the handling schedule. We are training staff to report this behavior, which we hope will be as rare in the future as it has been up till now.


Photographer’s note: The clear liquid in the photographs is water. No cockroaches were harmed in the making of this story.


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Frequently Asked Questions

Frequently Asked Question #1: Can I ask you a question?


Answer: Yes! Please – ask another!

Animal Caretakers get asked a lot of questions – a lot of good questions! Here are some of our most popular.




FAQ #2: Are those snakes poisonous?


Answer: No, our snakes are not venomous. All of our snakes are constrictors, which means they squeeze their prey to death before they eat them. Our snakes don’t have to squeeze their food to death because we give them previously frozen rats. Dead prey is safer for the snakes because it can’t fight back and potentially injure them. Still, our constrictors squeeze their prey instinctively.

FAQ #3: Do you feed the naked mole-rats to the snakes?


Answer: No. The naked mole-rats are kept completely separate from the boa constrictors. Even though naked mole-rats sometimes die naturally, and the snakes would probably find them pretty tasty, we feel that we would be crossing a morbid line to offer our naked mole-rats up as food.

FAQ #4: Don’t sea anemones sting?


Answer: Not our Puget Sound sea anemones. You may feel a mild stickiness when you touch the anemone’s tentacles but that’s all. If you were a tiny sea creature, that stickiness would feel like a sting.

FAQ #5: Do naked mole-rats eat their babies? I think I saw one eating a baby!


Answer: Perhaps what you saw was a mole-rat eating a carrot? Unlike pet hamsters and other rodents in captivity, mole-rats rarely resort to cannibalism. In fact, when a mole-rat dies, it is more likely that the colony members bury them in the bedding.

FAQ #6: Are those the cockroaches they eat on “Fear Factor?”


Answer: Yes [sigh]. Madagascar Hissing Cockroaches are said to be delicious and high in protein. Some cultures consider them a delicacy. But we would never eat just any insect without thorough knowledge of its safety. Some insects are toxic and they all carry germs!

FAQ#7: How do the naked mole-rats know that the potty chamber is their bathroom? They can’t read the sign!


Answer: What do you think? Do you have a cat? Does she go in a litter box? Have you noticed dogs like to go where other dogs have gone? It’s because of the smell, right? And if you look closely, you’ll notice our naked mole rat potty chambers are isolated with only one entrance. This keeps the smelly room away from their living areas. Mole-rats have an excellent sense of smell!

FAQ #8: Will the hermit crab bite me?


Answer: Well, it won’t bite you … but it may pinch you, and then just enough to hold on. It’s more likely that when you pick up a hermit crab, the little critter will scurry back into his shell. It’s afraid of you!

FAQ #9: Where is the naked mole-rats’ water bottle? My hamster has a water bottle in his cage.


Answer: They don’t need a water bottle or dish. Naked mole-rats live underground in dry desert conditions. They have adapted to get all their moisture from their food. Because they live in cramped tunnels, the humidity is very high. Their need for moisture is not the same as your hamster.

FAQ # 10: What are these things? Axo …??


Answer: Axolotls, “ak-suh-lot-l.” Although they look like big tadpoles, axolotls are actually amphibians that never go through metamorphosis. You probably won’t find them in the wild – they come from areas of Mexico that are heavily populated and they are nearly extinct in nature. Axolotls are studied for their ability to regenerate their limbs.

Any other questions?


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It’s all part of the job!

By Sarah Moore, Life Sciences Manager

Once in a while, an appointment on my calendar is so bizarre that even I wonder what kind of job I signed up for. This whole week is full of them. This week, I will “walk around picking up trash”, and check to make sure that the “butterfly cart gets restocked”. In one wacky day I have a 9:00 am “wild oceans adventure” a 10:00 am “discuss cockroach pigment with Brigid” and a 10:30 am “mist snake heads with Holly”. I end the week with “mole-rat cam follow up”.




So what do all these silly meeting topics really mean? Some of them are fairly mundane. Walk around picking up garbage is just that. Each week, a team led by our horticulture staff, Jeff and Maida, walks the grounds, cleaning up litter. We like to keep things looking their best. Some trends we have noted: people are becoming more conscientious about correctly disposing of food wrappers and bags. However, smokers, gum chewers and dog walkers can make a huge difference by packing out their litter.


Our Tropical Butterfly House is full of lovely butterflies, each with a brief but glorious two week life span. When they die, many butterfly’s wings are still colorful and pretty. Rather than destroy these intact and valuable items, we prepare them for a second existence in our Butterfly Discovery Cart, where children get to observe, appreciate, and even touch a butterfly wing.


Wild Oceans Adventure is a summer camp offered by our camp program. One of the activities campers get to enjoy is watching and participating in a tide pool feeding. Kids learn how animals eat in the wild, how we care for them here, and how to be a respectful guest next time the visit a beach.


Why on earth am I discussing cockroach pigment? There is a rumor among new staff and volunteers, that our Madagascar hissing cockroaches get more pigment and grow darker as they age. No one knows where this unverified fact began. Since it is essentially a new hypothesis, we don’t have any data on whether it is true. Brigid, who supervises our Discovery Corps program is interested in running an experiment to see what really happens.


Holly, our Presentation Supervisor, and I have been tasked with analyzing our snake handling practices, to make sure we have all possible safety measures in place. Since we know that most snake bites are related to feeding accidents, we wanted to develop a clear protocol to let snakes know when they were going to be handled but not fed. One way to do this is to lightly mist water on the snake’s face before handling. This may sound unpleasant, but our snakes relish water in nearly any form, and would develop a pleasant, but non-food related association between a refreshing mist of water and an upcoming presentation. This is in theory. Holly and I want to prototype the process and see how the snakes really react before letting our staff do it.

I’m going to let my last appointment, “discuss mole-rat cam” hang out there as a teaser for now. This article is already long enough, and I hope to have a full story on the cam in the near future.
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The Fearsome Threesome!

With the Goose Bumps! The Science of Fear exhibit now open, fans of Pacific Science Center’s arthropods will have another place to visit with some of their favorite animals. People who have avoided our Insect Village due to a dislike of bugs now have a chance to rethink their feelings. Three species are featured in the exhibit in ways that encourage our guests to explore and challenge their fear of bugs.

The species we chose reflect the reactions we sometimes hear from our guests, as well as the fears of some of our own staff.



Many people have a deep, some say innate, fear of spiders. The Chilean Rose Tarantula (Grammostola rosea) is a calm species of spider. They would rather avoid trouble than face it. When threatened, they are more likely to attack by shooting leg hairs, causing skin irritation, than they are to bite. Even if provoked to bite, their venom is not dangerous to humans. Our tarantula is nearing time to shed her skin, something tarantulas only do once each year. Her exoskeleton is balding right now; soon she will have a new, silky growth of pink hair. She prepares by building herself a nice, comfortable silk pad to lie down on. Her species doesn’t like to touch rough surfaces.


Fear of cockroaches is fairly common. Most people don’t specifically fear being harmed by them, but rather dislike the idea of having them in the home. The Madagascar Hissing Cockroach’s (Gromphadorhina portentosa) natural habitat is the outdoors, which may make them less threatening. They are familiar from popular culture, and are also the one insect Pacific Science Center invites our guests to touch. Touching butterflies can hurt their wings, but cockroaches’ reputation for robust good health is deserved – they can be held and pet by hundreds and remain unharmed. But save the hand sanitizer for after you’ve pet them. It contains ingredients that dry their skin, and is much more of a threat to them, than they are to us.


The Desert Centipede (Scolopendra sp) was chosen for this exhibit because our Life Sciences Manager, Sarah Moore, admits that it is the one invertebrate she fears the most. This centipede can deal a painful bite and is larger than your garden variety. It is also far more mobile than most venomous creatures, running after its prey and catching it with its fangs. But in truth, Sarah’s fear is out of proportion to the damage this arthropod can inflict. Unless one had specific allergies, a bite would hurt but do no lasting harm. Active predators, centipedes are one of the beneficial animals that help keep pest insect populations under control. Without centipedes, spiders, and other carnivorous arthropods, we would have more damage to our gardens and more bugs in our houses!

What insects or arthropods do you fear? What makes them scary? What would make them less scary?


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Meet the Hissers

Some people might get the impression from this blog that the only animals we have at Pacific Science Center are naked mole-rats and butterflies. Well of course that’s not true! The Life Sciences staff is very proud of the wide variety of animals in our care. In order to alleviate that impression, from time to time we will feature some of our less celebrated inhabitants. Today's featured animal resides in the Insect Village.


Watch Science Interpreter Jim McNamara acquaint us with the Madagascar Hissing Cockroach.



Next time you visit Pacific Science Center stop by and get up close and personal with our Hissers because unlike our butterflies, you can touch them!

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Hisser Mites

Animal Caretaker Adrian Eng and Discovery Corp Summer Intern David are waging war on the tiny mites that live on our Madagascar Hissing Cockroaches. This is Adrian’s first report from the front.







If you’ve ever handled a Madagascar Hissing Cockroach, you may have noticed some teeny tiny invertebrates crawling across their exoskeleton. These are mites and they call the cockroach’s body their home. Like travelers on a cruise ship, they move to and from different food sources utilizing our beloved roaches as their mode of transportation.


This mite species, Androlaelaps schaeferi, is not a cockroach parasite, as some scientists and hobbyists first believed. Instead, they perform commensalism, where one animal benefits while the other is unharmed and unaffected. A recent study from scientists at Ohio State University suggests they may even be beneficial to cockroaches, feeding on organic matter that would otherwise grow fungus. As beneficial as these mites may be, at Pacific Science Center we felt that an excess growth of mites was overly disturbing to the many staff and visitors that handle our cockroaches every day.

I teamed up with our Discovery Corp Summer Intern David and decided to wage a war with the mites. Our first goal was to reduce mite populations so that people are at least unaware of their presence. Our second goal is to figure out how to keep the mite population manageable in the long term.


We came up with a few techniques. Sweeping the mites with a soft brush seemed the most obvious choice. We also used very fine tweezers to remove mites one by one. This method was very tedious but effective. A more aggressive approach was dunking the roaches in water, which helped to loosen and dislodge the mites living on the body. This seemed uncomfortable and possibly dangerous for the roaches and the outcome was only moderately effective.


The most aggressive approach was using CO2 to incapacitate both the mites and the roaches. When they were both knocked out we were able to use an air canister to easily blow the mites off. This seemed the most effective technique but also the most invasive. Another suggested method was to dust the roaches with flour, something we will have to test the next time around.

This weekend we will begin our second round of treatment. I recently checked in on our roaches only to find that most of the mites have already returned in just a few weeks. As disappointing as this news can be, we are still determined to control the population of mites and are excited to find the best way to procure happy handlers and happy cockroaches.


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