FINAL LAB PACKET: Tarantulas & Climate

This topic submitted by Allison Mouch, Audrey MacWood, Kelly Alter, Nick Anderson (,,, at 12:39 pm on 12/7/01. Additions were last made on Wednesday, May 7, 2014. Section: Dr. Hays Cummins

Western Program, Miami University

Welcome! You could say that 108147 Spider Lovers stopped by. Enjoy!


This lab is set up to research and observe two different tarantula species (Pink Salmon Brazilian Birdeater- Lasiodora parahybana and California Ebony-Aphonopelma eutylnum) and their reaction to the environment around them in varying climates. They will be tested in three different climates: one above average, one below average, and one at room temperature (the control). Their weight, span, food intake, and behavior will be closely observed by the four lab members, as well as the rest of the class, for the duration of the semester. The observations will take place once a day, twice a week, for the next four weeks.

I. Introduction

Very little is known about the history of tarantulas because they have no external skeleton to fossilize (tarantulas online).

Tarantulas are different from other spiders because:
-They use two sets of book-lungs to breathe.
-The fangs of tarantulas move up and down.
-They have two claws and two adhesive pads on each foot.

The tarantula has long excited the imagination due to its great size and notorious hunting abilities. Known throughout the world by several different names (ex. the aranus peludas, or hairy spider, in Spanish America), the tarantula can be found in almost any country worldwide, from Central America to Australia (Tarantulas online). Here in North America, where over thirty different species of tarantulas make their home, these creatures are thought to be quite dangerous to humans, although this stigmatism is rather undeserved (Bear). The majority of tarantulas, while poisonous, will not hurt humans unless thoroughly provoked (desertusa). They harbor formidable fangs that contain poison, and when threatened, the tarantula will assume an attack position by throwing itself back on its haunches and lifting up its front legs (Strener). While this stance is quite intimidating to humans, it serves as a deterent to small mammals and enemy insects (Kevan)

Tarantulas are known as one of the world's most exceptional predators because of their extreme hunting skills. The tarantula has very poor eyesight and must rely on sense of touch to pursue and capture its prey (Douglass). Some Brazilian tarantulas have been known to eat small birds, snakes, lizards, and rodents, but most North American tarantulas feed on insects such as grasshoppers and other such creatures. These eating habits depend greatly on the tarantulas' living climate

When referring to living climates, tarantulas live in many varying climates across the globe. Some species reside in areas with heavy undergrowth and dense forest, while other species make their home in very arid, desert-like climates (Douglass). Still others have evolved to become arboreal and live in trees, which enables them to hunt small birds. Aside from these species, however, almost all tarantulas prefer to burrow into the ground and live in the safety of an earthen nest (Reichling).
The Classification of Tarantulas
Kingtom: Animalia
Phylum: Arthropod
Subphlum: Chelicerata
Class: Arachnid
Order: Araneae
Suborder: Opisthothelae
Family: Theraphosidae
(Tarantulas online)

Tarantulas are very important to our environment because their hunting skills make up an important factor in the food chain(Vener). Tarantulas keep insect and small animal populations at bay while staying out of the way of human activity. Being a fairly anti-social creature, the tarantula poses little threat to humans while providing a much needed service to the environment.

The purpose of this lab is to study the behavior of two species of tarantulas in varied climates. We will be studying their eating consumption, weight, span, and activity level. The question our lab group intends to investigate is what, if any, affect does a change in climate have on the daily activities and growth of a specific tarantula species, and how does that species compare to a completely different species in these aspects of change. The tarantulas will each be raised in their own container, a plastic Tupperware box approximately four by three by three inches in dimension. There are six tarantulas of each species, half Pink Salmon Brazilian Birdeaters and half California Ebony tarantulas. Two of each species will be put into each established climate: Two at normal room temperature (the control group), two above, and two below.

The tarantulas will be observed once a day, two days a week, for an extended period of time (ranging approximately fours weeks in length). Each day the data will be recorded for further use. Our hypothesis is that the Brazilian Salmon Pink Birdeater will be more active than the California Ebony species in general, and that the Birdeaters will grown larger in weight and span than the California Ebony species as well. We also predict that both the tarantula species will be most active at room temperature. In the below average temperature we believe that the tarantulas’ activity level will slow down and therefore they will consume less food and weigh less than in the other climate divisions. Our predictions for the above room temperature group are that the tarantulas will react in a similar manner as the below room temperature group, acting lethargic across the board.

With this experiment we hope to gain a better understanding and appreciation of tarantulas. In particular, we hope to gain more knowledge on the two specific species of tarantulas that we are raising, the Brazilian Birdeaters and California Ebonies. We want to learn about their specific eating habits and how they grow, as well as at what rate. Ultimately, we hope to successfully raise twelve tarantulas in three separate environments.

Our interest in this project stems from an overall group interest regarding tarantulas and their importance in our ecosystem. Not to mention the fact we like scary bugs! We just thought that raising our own tarantulas might be more interesting than researching those which other people had already raised, plus it would be a good learning experience and we could ultimately start our experiment on a brand new slate!

II. Relevence

Tarantulas are perhaps the most valuable yet the least understood of all species of spiders found worldwide. They can be located on almost every continent, in practically every country across the globe, and are widely regarded as supreme yet dangerous hunters (Adams). What humans may not know is that most species of tarantulas are quite docile and harmless, deploying their attack mechanisms only towards their prey and not towards people. Tarantulas, unlike their spider counterparts, do not weave webs, but prefer to catch their prey by a pursuit and capture technique (Adams). In addition to this information, tarantulas have extremely poor eyesight, and must hunt using their other senses, particularly smell and touch(Janssen). As a group, we decided that researching tarantulas might be beneficial for many reasons. Not only were we all (for the most part) enthralled by the species, but we wanted to know how they were affected by climate change. Taking into the experiment our knowledge on how humans and other mammals react to extreme temperature changes, we were interested to find out what a tarantula's behavior might be, and how specific climate changes would affect the species physically. Through research and observation, we hope to come out of the experience with a better understanding of the tarantula species, as well as with some specific information that might be helpful in comparing different species of animals worldwide and how they are affected by the changing climate and therefore changing ecosystem.

III. Materials & Methods
Six Pink Salmon Brazilian Birdeater Tarantulas
Six California Ebony Tarantulas
Twelve plastic Tupperware containers
One heat lamp
Standard baby crickets
Weighing viles
Electronic scale
Measuring tape
Paper towels
Nature (dirt) for tarantula environment

Check Out Our Tarantula Data Sheet!

The tarantulas will be placed in three different climates, one above temperature, one below temperature, and one control climate (room temperature). The tarantulas will be divided by species, and two of each species will be placed in each respective environment, making it four tarantulas per climate. Group members will check the tarantulas twice a week for approximately four weeks, recording tarantula weight, span, and general behavior, as well as cricket weight, the amount of crickets fed to each tarantula, and the amount of food the tarantula had consumed from the previous feeding. Moist paper towels will be kept in each container for the tarantulas’ benefit, and the cages will be monitored closely for any mold or unhealthy circumstances that might occur.


we expect to spend about a month collecting the data stated above on out tarantulas. The two weeks before we begin collecting data, we will introduce the tarantulas to their environments and get them settled in their specific climates. We hope this will help them stabilize before we begin our experiment. After approximately three weeks, the class will be asked to participate in our experiment, as elaborated on below!

Soundness of Experiment

Our group believe our experiment to be sound because we are using a control climate (room temperature) to compare both sets of tarantulas to, and we also have two tarantulas of each species in each climate, providing us with two sets of data to compare statistically. Originally, we were planning to divide the species into three separate climates, and then keep one tarantula of each species in the dark and one in the light. This idea was negated because we felt it would undermine the statistical soundness of our experiment, owing to the fact that only one tarantula of each species would be in each specific environment. In the setup we decided to use, we have two tarantulas per species per climate, and this number allows for much more comparison within species and between species.

Class Involvement
This lab is a difficult one to involve outsiders in due to the fragility of the tarantulas and the amount of time it takes to care for them. Therefore, our lab group decided to involve the class during our presentation a few weeks ago, where we invited everyone into the lab to help feed, weigh, and measure each tarantula. Members of the class, along with a group member, divided into three groups and collected data, caught crickets, weighed the tarantulas, and took the span of each little creature. Although many members of the class were quite squirmish about touching the tarantulas, we experienced an overall enthusiasm and willingness from them to help in our experiment.
IV. Results

BehavioralObservations and Quadrant Data

Statistical Data Concerning Weight, Span, and Cricket Consumption

Graphs & Charts

This chart explains the relationship between time and weight increase in our Brazilian Birdeater tarantulas.

This chart explains the relationship between time and span increase in the Brazilian Birdeaters.

This chart takes into account both the span and weight increases in the Brazilian Birdeater tarantulas over a period of time.

This chart, similar to the ones above it, represents the relationship between time and the California Ebony tarantula’s weight increase.

This chart expresses the relationship between the California Ebony’s span increase over time.

This chart once again takes into account both the span and weight increases in the California Ebony tarantula over a period of time.

These two graphs display the relationship between the two tarantula species and their respective weight growth over time.

These two graphs display the relationship between the two tarantula species and their respective weight gain as compared by location (above, below, or control temperature).

V. Discussion

After four long, grueling weeks of time-consuming measurements, observations, caring for and chasing after tarantulas, our project has come to a close. What we are left with is an exorbitant amount of information concerning our tarantula’s growth, eating habits, and climate preferences in the form of statistical data longer than we are tall. Oh yes, and we also have eight tarantulas, in case anyone is interested. Through acts of God, four of our subjects perished during the duration of our experiment, either from asphyxiation or giant crickets. However, their deaths are not what we are here to discuss, so we will move forth into explaining the results of our experiment.

The data is quite obvious in pointing out the fact that our Pink Brazilian Birdeater tarantulas grew the largest and fastest out of either species. We were expecting this result, due to the fact that the Birdeaters were expected to grow larger than the California Ebonies, and so it only made sense that their growth rate would be faster than the other species. What we did find that was interesting was that both tarantula species had similar growing rates, as can be seen in the above graph comparing weight and species over a period of time. While the Birdeaters obviously weight more, they are seen to be growing at practically the same rate as the California Ebony spiders, an interesting observation. It is obvious by looking at the chart below to see that there is a significant difference between the two species’ weight gain. What is striking about this graph is the way that the two graphs mirror one another.

What we found to be less obvious was the Birdeaters’ span as compared to the California Ebony’s. Basically, we found that there was no significant difference between the two species span growth over a period of time. We found this to be strange because the Birdeaters’ span was supposed to be much larger than the California Ebonys’ span, so we might owe this to a miscalculation on our part. At times during the experiment, while measuring the tarantula’s spans, they would curl their legs up, making it difficult for us to produce an accurate measurement.

Although all this other data is relevant to our experiment, our main focus was on the affects of different climates on the different tarantulas. We saw drastic variations between the two species of tarantulas and their respective climates over the course of four weeks. For example, our below room temperature tarantulas thrived in growth as well as span. On the whole, they were most active as well, especially LP2, who is arguably the largest and fastest tarantula we have! The California Ebony species were found to be largest in the control group, but only by a hair. Generally speaking, there was not a significant difference between the control group of California Ebonys and the below room temperature group. Therefore, we are making the conclusion that below room temperature is the most conducive environment for tarantulas to live in.

The worst environment we found varied, depending on the tarantula species. For the California Ebony species, the above room temperature climate was detrimental to their health. We lost both our tarantulas in that climate, although the Birdeaters did survive. However, the Birdeaters in the above room temperature group were the smallest of all the surviving Birdeater species. While the graph seems to show the above room temperature Birdeaters as being pretty large, the data cannot be taken at face value, for the control Birdeaters died in the third week of testing!

The control environment (room temperature) proved to be our most surprising environment, for we had expected both species to thrive here. However, only the California Ebony tarantulas survived in this climate. They were a healthy size, but fairly inactive when compared to their below room temperature siblings. The Brazilian Birdeaters seemed to be doing okay growth-wise, but for reasons unknown perished during the final week of observation. One appeared to have died while molting, and the other could have died from asphyxiation. This could have factored into the accuracy of the results, but the bottom line is that we feel the below room temperature climate had the best affect on both tarantula species’ growth rate, span, and behavior.

If we were to continue on with this experiment, we think we would attempt to have more tarantulas in our experiment. That way, the amount of data collected might be more accurate and less skewed by statistical error (i.e. random tarantula deaths). We would also increase the variables tested. While we attempted to record the tarantulas’ typical location, the data could not be included in our graphs due to its inaccurate nature. In the future, we might like to test for tarantulas adaptation to light or dark, or find a more accurate way to test temperature. At any rate, we believe there is still much to be learned about tarantulas, it is just a matter of whether or not we’d like to investigate another area of science.

Sources of Error

After completing the requirements of this lab, our group reflected on the events of the past six weeks and came to some conclusions about how we might have accomplished the lab more exhaustively. Some key points came to mind right away concerning better ways to go about the lab, especially in “engineering” the temperature-specific environments the tarantulas were to live in. For instance, it would have helped our experiment a lot if we had used thermometers to measure the temperatures of each environment. The way we did it originally, without thermometers to help us regulate temperatures, served its purpose but was probably not as accurate or effective as it would have been had we actually payed closer attention to the temperatures of each environment. This could account for a certain amount of statistical error. Another source of error that was not so much our fault was the fact that our heat lamp kept being stolen for other experiments in the department. This also resulted in a less than perfect environment for our tarantulas, and so we cannot totally rely on our statistics to be accurate due to this apparent fluctuation in temperature. One final factor that may have influenced our results was the fact that we just did not come up with enough data between twelve tarantulas. Had we been allowed to have fifty tarantulas, more data could have been collected and compared, and our research may have been more sound than it is today.

Final Presentation

For Further Info On This Topic, Check Out This Website:

You Know You Love Tarantulas When… (Tarantula Anecdotes)

Our beloved California Ebony tarantula “Gimpie” was not always so beloved. In fact, he was just one of the gang when we first received him in the mail. However, a few weeks into our experiment, Gimpie received a dubious blow. Over the course of a few days, the crickets residing in his home grew to massive proportions, deciding in the end to make a meal out of Gimpie (at the time known as AE3). After being attacked and beaten, our lab group found Gimpie lying in a heap with two legs lost and his life fading before our eyes. We were so devastated by this, since we had just lost one other tarantula to crickets earlier that day, that we made it our personal goal to keep Gimpie alive. I am happy to say that today Gimpie is one of our strongest remaining California Ebony tarantulas, and we all love him very dearly. With only six legs to his name, Gimpie is going strong!

During our cricket-eating scare, our lab group was quite weary to put live crickets in the tarantula homes. After one tarantula had been eaten and two mauled, we had reason to worry. Taking this into consideration, one day Nick decided to lend a helping hand to one of our fading little friends. He captured a number of crickets in a vile, and after surveying them a bit, began to shake the vile vigorously. The crickets were rendered senseless, but just to be sure he’d done the trick… Nick speared one with the tweezers to seal the deal!

While Kelly is not too fond of tarantulas, what she hates even more is crickets. We all hate crickets. Crickets suck. They smell bad, the jump around a lot, they’re ugly… Anyone in their right mind hates crickets. At the end of this experiment, while some of the tarantulas may actually be missed (maybe??? anyone???), the crickets will not be. In fact, we just might take the stupid cricket garbage can and drop it of the roof of Boyd. And then spear them all with tweezers. End of sentence.

Apparently tarantulas like leather jackets. You’ll have to consult Audrey about this one, but if any of you were at Spiders and Ciders night, you would know that tarantulas enjoy cowhide possibly more than you or I do! In fact, this specific tarantula decided he didn’t want to leave the comfort of Audrey’s arm (and leather jacket), and was willing to fight Hayes for the right to remain on Audrey’s arm. Scary, yes… but we had the situation under control!

Media Moment!

  • Take a look! Quicktime SLIDESHOW Students held "Vega" (Cyclosternum sp. (Costa Rican Red Rump)) during a recent Spider and Cider Night in the School of Interdisciplinary Studies at Miami Univ. Many students had never held a tarantula before. It was terrific!


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