Wednesday, July 16, 2014

New Website

Dear followers of Tim's Fertile Turtles.  I have a new website and blog where future postings will go.  Please visit my new website at  Thank you!

Friday, November 9, 2012

TREE students talk about their research!

The 2012 TREE program students give a brief explanation of their summer research. Here from all three teams:

Thursday, October 4, 2012

Anole eating anole!

Today we had another first for the Lizard Project.  While on island H capturing lizards, we found a green anole eating a brown anole.  While other people had previously observed this happening, we had not seen this on our islands, until today.

As I was looking for lizards, some rustling on a nearby palm frond got my attention.  Expecting it to be a lizard to noose, I crouched down ready to capture it.  Thats when I found an adult green anole munching on a hatchling brown anole. The brown anole was still alive and struggling, but looked like the struggle was going to be futile.  This was an exciting find for us.

Wednesday, October 3, 2012

We found eggs!

Earlier this week I wrote a post about a nest-site choice study that Aaron and Dan had done in the lab.  However, anole nests are notoriously difficult to study in the field- very little is known about anole nesting. However today, we found two anole eggs on one of our islands, which was very exciting for us.

Reptiles have varied reproductive  strategies.  Some give live birth, which is known as viviparity. Most reptiles, however, are oviparous, which means they lay eggs.  And most of these oviparous reptiles lay many eggs in a single clutch.  Anoles, however, lay a single egg at a time.  We are not certain why anoles lay only one egg, but this is a question some evolutionary biologists have studied.  One hypothesis is that the female can escape predators more easily by only carrying one egg at a time.  There are many other intriguing hypotheses, however.

Whatever the reason, we were excited to find two anole nests (which consisted of one egg each!).  Check it out

Lots of Lizards, big and small

We have been catching lizards for four days now, and we have nearly eclipsed the 500 lizard mark!!!  That is a ton of lizards, even for us!  There are several reasons we are having such lizard catching success.  Overall, the populations have established very well and are growing.  But another important factor is the time of year. 

Last time we came in April just before the reproductive season.  Many of the babies from the previous summer had died and the surviving ones were relatively large.  This time, we are coming in October, at the end of the long reproductive season.  The eggs that were laid between April and August have now hatched and there are baby lizards everywhere.  Many lizards don’t survive to adulthood, but by monitoring the lizards right after they hatch, we are very likely to catch the babies. Thus, this time of year has more lizards than any other time on the islands.

Another cool thing about our project is we are getting "recaptures".  When we capture a lizard, we will mark its toes and release it back on the island.  When we come back on a trip 6 months or a year later, we will be able to figure out if we had caught that lizard before and then learn about how much its grown and what traits may have helped it survive.  On this trip, we have already recaptured two "Founders" or the original lizard we released in April 2011. They have been out on these islands for 1.5 years, which is very old for an Anole lizard in the wild.  And very cool for us!

Anole lizards have no parental care, so the baby lizards pop out of eggs as miniature versions of mom and dad.  They are feeding on really small insects and evading predators from day 1.  They only thing that the youngsters aren’t worried about that the adults are is mating, but that will wait for now. These lizards grow very fast and as you can see in the video, a baby lizard might grow up to 70 times its size as a baby.

Sunday, September 30, 2012


Dan Warner, David Delaney and I started catching lizards on our islands yesterday.  On Day 1 we caught 151 lizards, which is a new record!!  We think the lizard populations are probably doing very well!  Today is Sunday, and we spent a half-day in the field catching lizards, and are now in to measure and mark all the lizards we have caught so far.  It will be a long night with the lizards as we have to measure, weigh, mark, and take tissue samples from all of them!

Check out this video demonstration on how we catch lizards.

Partnering with Youngzine again!

Youngzine is a news website targeted towards young people, and they are highlighting our science research again!  Check out the following article!

Lizard Team uses labs and field work

 When asked about where a scientist works, most people would probably think of the laboratory.  And while it is true many scientists spend a lot of time working in labs, that is certainly not the only place they work.  Here I will highlight a lab experiment performed by the Lizard Team, as well as the field work.

Lab work: What are the advantages?

Members of the Lizard Team have studied anoles in “the lab” setting. While many wild animals are difficult to study in the lab, the brown anole is not.  Anoles do great in captivity. as they readily eat, mate and reproduce.  Advantages of the lab are that conditions can be carefully controlled, which allows the scientist to expose the many lizards to the same conditions to see how they behave.

Lizards in the lab, with nesting containers at the bottom of the cage.

Aaron Reedy and Dan Warner recently published a paper on some lab research.  However, the lab was not at a traditional research institution, but was Aaron Reedy’s high school classroom!  For this experiment, the students helped Aaron and Dan answer an original research question:  Where do mother anoles like to lay their eggs?  And why has this nesting behavior evolved?    To do this, they set up 20 cages with 3 female lizards and one male lizard each.  In each cage they also placed 5 different containers with soil that lizards could lay eggs in.  Each container had a different amount of soil moisture- ranging from 0% to 75% moisture.  Each week students checked the containers for eggs.  It turned out that mom’s really preferred to nest in the moistest nests.  A subsequent incubation experiment showed that eggs from these incubation conditions were more likely to hatch, and the hatchlings were larger, and survived better. Dan, David (a high schooler) and Aaron concluded that evolution has favored moms that are more likely to lay eggs in these optimal nest conditions, which is why they showed this behavior.   This is an excellent example of how a lab experiment helped them answer a research question. Don’t you wish your classroom had done an experiment this cool!

Field Work: What are the advantages?

While lab work is very useful, the natural world is far more complex.  So studying animals in their natural environment might give us a better idea of what is really happening in nature.  However, it can be difficult to manipulate variables in the natural world.  Dan Warner, the Lizard Team leader (also known as the Lizard King), has utilized islands to get the best of both worlds.
 Lizards can't get on or off the island, so its perfect for experiments
For these lizards an island has all the complexity of the natural world except for one thing: being able to come and go as a lizard pleases. The water separating the islands from each other and from the mainland are impenetrable to these lizards. The only way a population increase or decrease is births and deaths, not immigration and emigration.

For the Lizard Project, this feature is excellent.  By using islands, we have been able to manipulate the sex ratios of the lizards. On some islands there are more boys than girls, other islands more girls than boys.  Other than that, these lizards are living their natural lives. We will be able to learn a lot about how a biased sex ratio influences various aspects of lizard biology.  More of that to come in future posts.

Friday, September 28, 2012

Lizard Team is back at it!!!

Hi Everyone,

This summer we had a record setting Turtle season and I have been very busy following up with this summer's experiments, analyzing data and writing papers, and sharing my research at the World Congress of Herpetology Conference in Vancouver.  However, right now I am in Jacksonville, Florida for another round of lizard catching for the Lizard Project.  I was in Florida back in March and April, and many students followed along my blog then.  Now for the first time since the last trip, the Lizard Team is back in Florida. While the Lizard Team was briefly reunited at the 25th Turtle Camp Anniversary, we are now ready to chase the lizards!

I will be tweeting from my @timsturtles account and the Youngzine (News website for children) will be following our progress again!  (  Check it out!

Thursday, June 14, 2012

Turtle Camp Research and Education in Ecology (TREE) Program starts!

For two weeks each year, 8 high school students join the graduate and undergraduate students doing research at turtle camp.  For these two weeks, these students are immersed in science research.  They participate in the ongoing projects associated with the Janzen lab, and have an opportunity to develop their own research projects.  Students generate their own questions, are guided through the process of developing a experiment or study that can answer their question, and have an opportunity to present their research to the public.  The Turtle Camp Research and Education in Ecology (TREE) Program is a rare opportunity for students of this age to engage in real science.  This year’s TREE program started on Monday, and we will get to know these students and their projects over the next two weeks.

25th Year Anniversary

For 25 years, Fred Janzen and his collaborators and students have intensely studied a population of painted turtles on the Mississippi River.  Those who have participated in Turtle Camp are now across the country doing great things.  On June 1st, we had our 25th year anniversary, drawing former students from across the country to spend a weekend at Turtle Camp.  This group of hard-working and dedicated scientists have produced new knowledge about one of the most fascinating creatures on the planet.  Fred deserves a big Thank You from us all for giving us the opportunity to engage in such interesting research.

Tuesday, June 12, 2012

Turtle Life Part 5: Spring Emergence

A baby turtle on its journey to water.
Black is all you ever have seen. You and your sisters are packed into your subterranean nest, and you have just endured a cold winter.  But days are getting longer, and sunlight more intense, and the soil begins to thaw and then warm.  On a hot rainy day in March, you and your sisters begin to claw your way through the moistened soil.  You have several centimeters to dig through, and you reach the surface.  Your first glimpse of light!   However, you are an aquatic turtle, yet mom put your nest far into the land.  For each meter she crawled out of the water, you have to crawl back.  With her size, she can walk that far in ten minutes, but it will take you days.  You are about the size of a quarter.  The lawn grass towers above your head.  Divots in the ground are like canyons, and slight rises are like mountains.  You cannot see the water directly, but you can sense it, and start walking towards the water.  Your dark colored carapace helps camouflage you, but there are predators everywhere.  Little blackbirds, blue jays, herons, crows, raccoons, bullfrogs, and anything else that can fit you into their mouth might eat you.  And if you don’t make it in time, you could dry out and die.  In early mornings and late evenings you march towards water, but its too hot in the middle of the day and too cool in the night.  Inch by inch, you get closer to your goal until you finally reach the swamp.  Your first swim in the water feels natural, as this is your real home.  While you still need to avoid fish, frogs, wading birds, and many other predators, you have already beaten many of the challenges you face.  If you are able to survive, you will come back to the nesting beach where you were laid, but 5 years later, to lay your first clutch of eggs.  Your first year of  life is now complete.

Turtle Life Part 4: Winter Months

You are a COLD baby turtle!
You and your sisters have hatched in your nest, and now position yourselves with your tail down and your head up.  Here, you wait.  You still have some yolk attached to your belly on the inside of your shell.  This yolk is all your nourishment until spring.   As proceeds, leaves turn colors, then drop off the trees above your nests.  Days grow shorter, nights grow longer, and winter approaches.  The temperature inside your dark nest begin to fall, your heart rate and metabolism really slow down.  Snow that falls above the nest acts as an insulating barrier to the cold.  Still, your shallow nest, and subsequently your own body temperature, drops below freezing.  Your body is specially adapted to withstand subzero temperatures.  Your body can “supercool” which means it can stay unfrozen in temperatures below freezing.  Even if it gets colder, parts of your body can freeze- mostly the liquid outside of your cells.  You are one of the few vertebrate animals on earth that can survive with your body temperature so cold.  However, the winter is still a dangerous time.  If it drops too cold, you may not be able to make it.  However, all you can do now is hope mom’s nest was in a place that is well enough insulated from the cold, that you won’t freeze to death.  You  can’t wait for the spring thaw and your first glimpse of daylight.

Sunday, June 10, 2012

Turtle Life Part 3: Summer Months

A developing turtle embryo!

Its now early July and you have been developing well. Your sexual structures have not yet developed and whether you will grow boy parts or girl parts is now being determined.  This years temperatures are about average, and your nest is in a sunny spot.  In particular, during the afternoon, there is no shade covering your nest.  These warm temperatures increase the developmental rate, meaning cells are dividing faster and your body is growing quickly.  When you are at a cooler temperature you develop more slowly.  Since you are at a warm temperature certain genes are telling your body to produce hormones that direct your developing tissue to become ovaries as opposed to testes.  This means you are a girl! 

Development proceeds rapidly as this summer is very warm. In early August, you are almost completely developed and it’s about time to hatch.  You have a special scale on the end of your nose called an egg tooth.  You slit the leathery shell and take your first breath of air.  Over the next day or two you will completely crawl out of your shell.  All of your siblings are doing the same thing right now.  Within a day, there will no longer be a nest filled with eggs but now a nest filled with you and your baby turtle siblings.   You might think that the next step is to crawl out of the nest, but in fact, your chances of survival are much better if you sit tight, and endure the coming winter months in the comfort of your nest.

Tuesday, May 29, 2012

Turtle Life Part 2: Early June

Now it is early June.  Your nest (luckily) was not sniffed out by a hungry predator, and you remain safely buried in the soil.  At this point, you chances of being found by a predator or very low, they mostly find only fresh nests.  However, about 70% of the nests around you were discovered and destroyed.  For the coming months, the most important thing for you is how wet and how warm your little spot in the soil is.  Mom chose a very sunny site to dig your nest.  There is very little shade on the south or west side of the nest, so your nest is very exposed in the hot afternoon sun.  Compared to most of the places around, your nest is relatively very warm.  However, more important than how shady your nest is, is just the weather itself.  You develop more quickly when its warm, but development slows down when its cool.  If your nest is very warm, you may hatch in early August, but if its a cool summer, you might not hatch until September. 

Your mom left you all the yolk you need to grow, but she didn't give you all the water you may need.  Unlike a bird egg, that has a shell that water cannot permeate, your leathery soft egg shell can absorb (or lose) water. If your nest is very moist, your egg will swell up, and may even allow help you be bigger when you hatch.  However if it floods, you won't be able to survive.  And if it is very dry, it may make growth difficult or even kill you.  So hopefully your mom's nest is about the right temperature and about the right moisture for proper development. 

As you have heard, nest temperature will determine whether you will be a boy or a girl. But the critical time for sex determination (known as the thermosensitive period) will not begin quite yet.  Once you are about one third of the way through your development, tempertature will begin to be important, but that is still a few weeks away.

Thursday, May 24, 2012

Turtle Life: Part 1 The first year of life for a turtle

Use your imagination for a moment, and put yourself in the shoes (or shell!) of a painted turtle during the first year of life.

Mom is digging you a nest!
The first few weeks of May:  You are a fertilized egg of a turtle, only a few cells big.  You are inside your mother, along with 10 other eggs who will be your brothers or sisters.  Each day, your mother is swimming around the slough, trying to eat as many aquatic insects, carrion, and aquatic vegetation as possible.  She needs this food so that she can supply you with a large amount of nutritious yolk.  This yolk is very important for you, because you will not eat a real meal for about 1 year!  Your mother is also trying to bask in the sunlight as much as possible so she has the energy to dig you a nest, somewhere on land.

May 24:  Today is an important day for you and your siblings. It is sunny, and warm, and mom spends all morning basking.  Around 5pm, she crawls out of the water.  She could crawl out only a few meters, but she doesn’t.  Mom walks out of the water and starts looking for just the right place to nest.  Which place is right?  Well, this is a challenging question!  Raccoons, skunks, foxes and coyotes would love to dig up her nest, and might even try to eat mom if they get the chance- so hopefully she can find a place where you and she can both avoid the predators. 
You and your siblings, buried with care in the nest!
She also needs to be concerned with your development.  She can’t sit on the next like a bird can or protect you from predators, so the only thing she can do is choose a good place.   If its too hot or cold, you won’t ever make it, but she can’t control the weather either.  So she has to choose a nest that will hopefully be the right temperature, but you may be at the mercy of the weather.  Also, if your nest is very warm, you and your siblings will all become sisters.  If your nest is cool, you and your siblings will all become brothers.  Perhaps your nest is in the middle, and you will have some brothers and some sisters!    

The covered up nest- well camouflaged from Raccoons.
Mom chooses a sunny place about 50 meters from the river.  She begins to dig. Your mother has extremely sharp claws and powerful hind legs.  She also has drank a lot of water, which she now releases on the nest as she digs, to help moisten the rock hard soil.  She carefully carves out a cavity about the size of a racquetball, with a narrow opening at the top.  Then, out you come!  You are no longer in your mom, but in the ground.  Your eggs is about the size of a grape, but mostly yolk.  You are still just a few cells large. She carefully packs you in, and covers you up, and crawls back to the water.  Since you are in an egg, and haven’t even developed eyes yet, it is possible you will never ever see your mother, because she is gone and isn’t coming back!  But she has done what she can to give you what you need to survive.  But this is just the beginning of a long year ahead of you!    Find out what happens next?

Monday, May 21, 2012

Turtle Nesting 101

Turtles are oviparous which means that they lay eggs.  Many other animals lay eggs as well, like birds, insects, amphibians, fish and other reptiles.  Whether or not turtles live in the water most of the time, they will lay their eggs on land.  The painted turtles that we study crawl out of the water, dig a shallow nest, lay their eggs, cover up the nest, and leave.  Forever!  That’s right.  After a turtle lays her nest  she never comes back.  So you may think a turtle is a pretty lousy mom.  But that is not so!

Turtle eggs are filled with nutritious yolk that help the baby developing inside grow.  These eggs are very sensitive to their environment- particularly how warm and wet the environment is.  So moms must lay eggs at just the right time, and in just the right place so that the nest is suitable for the developing eggs. 
At Turtle Camp, we monitor where and when turtles nest, and we measure how many eggs are in the nest, and how big each egg is. Over the past 24 years, the earliest date we have recorded a turtle nest was May 21. This year, there have already been 52 nests laid prior to May 21! Depending on where you live, you may have experienced a very warm winter and early spring.  Here at Turtle Camp it was a very warm winter and early spring. This warm winter has already influenced how the turtles are behaving!  Stay tuned to see how nesting continues through the coming weeks.

Saturday, May 19, 2012

Turtle Camp 2012! The 25th Year!

What is Turtle Camp?

25 years ago, a PhD student from the University of Chicago was looking for a place to find Painted Turtle eggs for a science experiment.  Somebody suggested heading to a Sand Prairie along the Mississippi River, near Thomson, IL.  As he was camping nearby on a nearby island, he noticed turtles seemed to love nesting right in there in the campsite!  That student was Fred Janzen.  Fred is now a Professor at Iowa State University and we now know that campsite as Turtle Camp.  And every year since that summer, Fred and his students have traveled to the Turtle Camp to research the turtles.

For 6 weeks each May and June, a team of researchers is stationed at Turtle Camp, trying to learn as much about the ecology and evolution of these animals as possible.  The Turtle Camp Research Team has very diverse duties.  On one of the nesting beaches, we walk through every single hour of daylight looking for nesting turtles, and take all sorts of information about each nest.  We also trap turtle swimming around in the river, and learn about those turtles as well.  We visit the Sand Prairie, which is a great habitat for turtle nesting, and for many uncommon reptiles to live (like the Hognose Snake and Ornate Box Turtle).  On top of all this, students have their own research projects going on.  Indeed, Turtle Camp is a busy place for the Turtle researchers. 

Who is the Turtle Camp research team?

Each year the research team is a bit different, and throughout the season different people come and go.  Right now, I am coordinating the research project. I am a PhD student at Iowa State, and  I am working with 3 Iowa State biology students, Jessica, Brooke, and Aubrey. Jessica is from Des Moines, and has been to Turtle Camp for 6 years (longer than I have).  She started coming as a high school student.  Brooke is in her second year at Turtle Camp, and Aubrey in her first. As Turtle Camp proceeds more and different people will be coming through.  Of course, Fred is still the primary Turtle Camp researcher, and is the reason there has been successful research continuing here for so long. 

What to expect by following along?
Over the coming weeks, you will learn that turtles are very fascinating and interesting creatures.  And you will also learn what its like to be a science researcher living in the field, studying animals in their natural habitats.  It will be a fun adventure for us, and I hope you will have a fun following along. 

Wednesday, May 16, 2012

Turtle Camp Begins!

On Monday we arrived at our Turtle Research site in Thomson, IL.  We will spend the next 6 weeks here doing science research, working mostly with Painted Turtles.  On Day 1 we set up our campsite and gear for the 6 week season, and purchased a lot of supplies and groceries.  Yesterday we set up a lot of turtle traps in the Mississippi River backwaters to try and capture as many turtles as possible.  And we also had our very first turtle nest of the season....  Our internet coverage is rather poor out here, but I will be sending you some videos and more updates soon.

To whet your appetite, check out this longer turtle trapping video from last years Turtle Camp.

Tuesday, April 24, 2012

Sex-determination explained

Ted ED partnered with Aaron Reedy (of the Lizard Project) to make this great video about the diversity of sex-determining mechanisms.

There is still a lot we don't know about sex-determination as well, which are areas of current and future research.