Desert Tortoises

Desert Tortoises


Ode to the Creosote Bush

A desert tortoise pauses under the shade of a creosote bush.

A desert tortoise pauses under the shade of a creosote bush.

The southwest desert is thought of as a barren landscape by many, yet you may be surprised to learn that the Mojave Desert is diverse with plants and animals, all conditioned to survive the extremes of this environment. The desert tortoise is a keystone species of this desert and well adapted to an arid climate. Desert tortoise burrows offer protection for other desert species from predators and harsh weather conditions, and they disperse seeds from the native plants that they eat, repopulating the desert ecosystem with them!

Although it’s unlikely you’ll have a random encounter with a desert tortoise in the wild, it is common to see Larrea tridentata, commonly known as the creosote bush. This is a dominant shrub of the desert southwest and where desert tortoises tend to build their burrows due to the soil stability resulting from the creosote’s root system.

A creosote bush provides shelter for ground dwellers.

A creosote bush provides shelter for ground dwellers.

The creosote bush is also the most drought-tolerant of the desert southwest, with a waxy coating on its leaves that prevents water loss. During times of extreme drought, old branches and roots of creosote bush die back, returning only when it rains. Although, this shrub isn’t a primary food source, is does provide shelter to many animals.

As a desert dweller, rain is rarely in the forecast for me, but when it is, my senses are stimulated by the refreshing odor in the air, and I have often wondered, what causes the rain to smell? Well, the unique camphor-like odor in the air is from the creosote bush! When it rains, this waxy layer on the leaves volatilizes, producing the smell of rain.

I’ve called the desert southwest my home for a majority of my life, yet I continue to learn and appreciate the wonder of the desert around me every day!

Pamela Flores is a research associate at the San Diego Zoo Desert Tortoise Conservation Center in Las Vegas, Nevada. Read her previous post, Students Help Desert Tortoises.


White Christmas for Juvenile Desert Tortoises

A tortoise burrow can be seen the morning after a nightfall of light snow. desert.

A tortoise burrow can be seen the morning after a nightfall of light snow. desert.

Juvenile desert tortoises released in September 2012 at the Nevada National Security Site are making their way through their first winter in the wild. The tortoises were snug tight in their burrows over the holidays when temperatures dropped below freezing and a light snow fell.

As ectotherms (cold-blooded animals), desert tortoises must utilize their surroundings to regulate their body temperature since they can’t warm their bodies on their own. Only a few inches of soil are enough to buffer air temperatures to allow the tortoises to hibernate through the winter without freezing. In a few more months, when the air temperatures begin to rise here in the desert, all of our translocated tortoises should emerge to heat themselves in the sun.

Jeanette Perry is a research assistant at San Diego Zoo Global’s Desert Tortoise Conservation Center in Las Vegas, Nevada. Read her previous post, Wandering Males, Jealous Boyfriends.


Internship at Desert Tortoise Conservation Center

Our student interns help desert tortoise conservation in a big way!

Our student interns help desert tortoise conservation in a big way!

Throughout 2012, the staff at the Desert Tortoise Conservation Center worked with students from a local high school, West Career & Tech Academy (see Students Help Desert Tortoises). The students were very interested in science and receiving hands-on experience, and we were happy to help out any way we could to expose the students to real-world experiences and to gain a little help of our own. West Tech started an internship program and asked us to participate; we, of course, were happy to help and keep the partnership alive. We thought of a number of projects the interns could work on and found the perfect fit. Our first interns, Gendie Gonzales and Cheyenne Taylor, were interested in participating in duties at the DTCC, but since it’s winter here, we had to come up with an indoor project that would benefit all.

The sample-filled tubes await organizing.

The sample-filled tubes are organized and banked, thanks to our interns.

An experienced biologist had collected over 4,000 biological samples (such as plasma, red plasma, red blood cells, ticks, and oral swabs) from desert tortoises at various Mojave Desert sites over the past summer. We needed help banking or organizing all the sample-filled tubes that were in plastic bags with a date on them when given to us. Banking these important samples is not an easy task and takes a lot of time and meticulous effort to ensure no mistakes are made. These samples are important, because they will be around for a long time and will help give us invaluable information about wild desert tortoise genetics and health.

The internship is a great way to give students a look into a career in conservation biology and give us a helping hand at the DTCC. We look forward to the continuing partnership in 2013!

Angie Covert is a research coordinator at the San Diego Zoo Desert Tortoise Conservation Center. Read her previous post, Promoting Desert Tortoise Care.


Desert Tortoise: Winter Improvement Tips

A desert tortoise patrols its backyard habitat.

As the temperature drops outside and desert tortoises are slumbering in their burrows, we here at the Desert Tortoise Conservation Center are busy catching up on projects around the site. This is also a perfect time for desert tortoise custodians to work on home projects and make habitat improvements for their own pet tortoise in preparation for the spring emergence. You might be a seasoned tortoise custodian or just getting started; either way, here are some simple and helpful tips for making the home habitat safe and interactive for your tortoise.

Tip 1: Escape-proof Your Yard
When a pet desert tortoise escapes from a yard, it isn’t usually a family member that leaves a gate open but a gardener or meter reader that didn’t know a tortoise was in the yard. Unfortunately, once a pet tortoise escapes, it is not always easy to reunite him with the custodian. An easy fix for preventing this mishap is to add a simple and removable gate barrier. The barrier should be at least 18 inches high and made of a solid material. A large piece of particleboard is a good option, which can be secured by placing four cinder blocks (one on each side) on both ends of the board. This design works great, especially if there is a need for the board to be removed temporarily. Once the gate barrier is in place, take a look at the entire fence line and make sure it is secure and free of holes or breaches.

Tip 2: Eliminate Hazards
Bundle up with a scarf and a pair of gloves and enjoy some family time, outdoors! This is a great time of year to clean up your yard and look for hazards that may harm your tortoise. Desert tortoises are excellent climbers, and they may try to climb over piles of debris or unused equipment, which can be hazardous if the tortoise falls backward, getting trapped on its “back.” Look for other hazards to fix, like an unfenced pool or water feature, which a tortoise could fall into. By sprucing up your yard this winter, you can make it a safer environment for your family pet this spring!

Colorful globemallow is a favorite food of the desert tortoise.

Tip 3: Spring Planting
Spring is right around the corner, so now is a great time to start thinking about greenery you can add to your yard when the weather warms up! Desert tortoises are natural foragers, and they love to roam the yard munching on plants and grasses. Tortoise- friendly forage such as globemallow, primrose, hibiscus, and Bermuda grass will help provide your pet tortoise with the right nutrition throughout the active season. Check with your local nursery for availability and growing recommendations for your climate.

Lori Scott is a research associate at the San Diego Zoo Desert Tortoise Conservation Center. Read her previous post, Desert Tortoises Spotlight Teacher Workshop.


Tortoises Spotlight Teacher Workshop

Workshop participants find a “tortoise” using radio-tracking equipment.

As we close in on our winter season at the Desert Tortoise Conservation Center, located in Las Vegas, Nevada, it’s a great time to reflect on some of the highlights of our busy summer. One new program we offered to local teachers through the Clark County School District was a desert tortoise education workshop. This past June and July, a total of 32 teachers took part in the workshops. We’re happy to report that the classes were well received, and the response has been very positive!

Although rarely seen in the wild, the desert tortoise is the state reptile of Nevada and an important keystone species of the Mojave Desert ecosystem. Getting kids excited about science and math can be a huge hurdle for many teachers, and this was one of our main motivations for developing the desert tortoise workshop. One of the goals of the workshop was to provide teachers with curriculum that spotlights the cool adaptations of the desert tortoise while focusing on the important roles it plays in the Mojave Desert. With a focus on biology, ecology, and conservation, teacher participants were provided with fun and interactive desert tortoise curriculum, which also fulfills the Nevada classroom standards in life and earth sciences.

Throughout the workshop, teachers became students and were able to participate in hands-on activities and demonstrations to simulate current research projects being conducted by San Diego Zoo scientists. For example, teachers participated in a telemetry demonstration, learning hands-on how researchers use telemetry to study tortoise behavior following a release back into the wild. As a part of the activity, participants used radio tracking-equipment to “track” a model tortoise (made of Styrofoam), which had been affixed with a radio transmitter and hidden under vegetation. It was fun to watch a group of educators weave their way through the desert in unison, following the sound of a radio receiver, which released a “ping” as the Styrofoam tortoise grew closer.

Educators who participated in the workshop earned one credit toward professional development education through the Clark County School District, and were provided with desert tortoise resource materials and activities, which can be adapted to their individual grade levels. After a successful first run, we will be offering the workshop again to local teachers in February 2013. We’re excited to provide educators with the opportunity to study the desert tortoise and return to the classroom with a range of tools to promote continued education of this amazing animal and the Mojave Desert ecosystem.

Lori Scott is a research associate at San Diego Zoo Global’s Desert Tortoise Conservation Center. Read her previous post, Desert Tortoises Pose for Photos.


Rain in the Mojave Desert

A desert tortoise prepares to snack on a desert mallow.

When most people think of the desert, they don’t think much about rain. Well, on August 22, the Mojave Desert experienced record-breaking rainfall, with some areas receiving well over 2.5 inches (6 centimeters) of rain within a 24-hour period, which caused major damage to the area. Most damage was due to washed-out roads and to low-lying property. But altogether, the desert had a much-needed drink for such a hot and dry summer.

Desert plantains have sprouted after record rainfall in the Mojave.

The aftermath of so much rain caused an explosion of plant life to appear throughout the desert. Some plants had not been seen in certain areas for many years. Plants such as the desert plantain Plantago ovate, desert mallow Spaerlcea ambigua, and golden bush from the genus Ericameria, just to name a few, started growing all over the desert. These plants are some of the desert tortoises’ favorite foods, which will help them have a full stomach before they go down for hibernation in the winter.

Daniel Essary is a research associate at the San Diego Zoo’s Desert Tortoise Conservation Center. Read his previous post, Rabbits, Rodents, and Tortoises.


Wandering Males, Jealous Boyfriends

Jeanette removes a transmitter from one of the released desert tortoises.

We’re currently at the tail end of one of our desert tortoise translocation projects. It’s finally time to say goodbye to the desert tortoises we have been tracking for the past year and a half, and over the past month or so we’ve begun the task of removing their transmitters. However, this is easier said than done. This project happened to end during the mating season, a time when males move long distances in search of females. One of our males went missing for five weeks and was found almost three miles from his old burrow!

Before we remove the transmitters, we do a final health assessment. We noticed damage to the underside of the carapace (the top shell) on many males. They are known to fight other males utilizing their gular horns to attempt to flip their opponent onto their back. Some male tortoises are bolder than others, and we came across a very bold resident male searching for a female one sunny morning. As my coworker, Jason Rose, and I approached a burrow that female tortoise #619 was occupying, we heard movement inside the burrow. Assuming it was the female we were tracking, we checked the burrow and saw a male tortoise charging at us! He came straight out of the burrow and blocked its entrance, trying to keep us away from his mate. His chin glands were enlarged, and he looked mad!

Here is tortoise #619’s very ardent and determined suitor.

Jason put some gloves on and moved him 50 meters (165 feet) from the burrow so we could get to the female. While waiting for the female to come out of the burrow, the male snuck up behind us and attempted to re-enter the burrow. This time we moved him 100 meters (328 feet) from the burrow to give us some time with the female. Moments later, the male returned and charged Jason. Knowing the female was not going to exit the burrow with the aggressive male in the area, we packed up and allowed the male to re-enter the burrow. He positioned himself facing toward us, in front of the female. Claiming defeat to the jealous boyfriend, Jason and I left the site.

Jeanette Perry is a research assistant at San Diego Zoo Global’s Desert Tortoise Conservation Center in Las Vegas, Nevada.


Students Help Desert Tortoises

Part of the West Tech Team

We recently collaborated with educators at West Career and Technical Academy here in Las Vegas with the goal of providing the students with an opportunity to coordinate their own projects! A few weeks and dozens of emails later, six technical high school students, along with their instructor, anxiously pulled up to the front gate of our Desert Tortoise Conservation Center (DTCC), excited for the first day away from their classrooms.

The team measures a desert tortoise burrow.

The DTCC is an enclosed 222-acre (90 hectares) site located in southwest Las Vegas, Nevada, with varying sizes of enclosures. I suggested the idea for the engineering and GIS mapping students to map artificial and natural tortoise burrows in a 10-acre (4 hectares) enclosure. With the use of GPS to mark data points and flags to section off the pen into grids, the students methodically walked through the pen marking artificial and natural burrow locations and orientations. I also suggested the students check burrows for tortoises, looking for a possible correlation between burrow orientation and occupancy. This information may be useful to us when adding artificial burrows to enclosures.

The map the students produced, showing burrow locations at the DTCC.

A second group of students had a different interest—plants! Their project was to create a photo book. The plan was simple: walk the desert taking photos and identify the common and scientific names of as many plants as possible! Walking through the enclosures, they also noticed a common location for soil tortoise burrows, under the bush most commonly seen in our desert, Larrea tridenta, commonly known as creosote.

“The Desert Tortoise Conservation Center project was an amazing work experience. It gave us an opportunity to see how things worked in the real world. I got to work with some of the tortoises and see how they ate and lived in their natural habitat. We had to think about ways to make the tortoises’ life better and easier for the people to take care of.”
-Michael Vogel

Everyone here at the DTCC looks forward to future collaboration with the community!

Pamela Flores is a research associate at the San Diego Zoo Desert Tortoise Conservation Center. Read her previous post, Desert Tortoise: Rainy Day Translocation.


With a Little Help from Our Friends

Boy Scouts Orlando Arnold, Jr. and Cory Chatterton are hard at work making artificial burrows for our tortoises.

I’ve spent over 10 years working in conservation, and no matter where in the world you end up, whether it’s here in the States, down in South America, or halfway around the world in New Zealand or Australia, one thing is painfully clear: there’s a lot of important conservation work that needs to be done and there never seems to be enough resources to get us to where we want to be. Though the budget shortfalls sometimes make the work a bit more difficult, one area in which I’ve been repeatedly amazed is the great support we often receive from members of the community and enthusiastic folks who come out and donate their time and a bit of sweat helping us get our work done. Conservation and the science behind it is not a solitary endeavor. Many people go into making every project succeed, and I just wanted to take this opportunity to remind all of you who may have helped with a conservation project (with San Diego Zoo Global or otherwise) or are thinking about volunteering that your time and enthusiasm really do make a huge difference!

Volunteer Simon Madill works on some fence repair for our on-site tortoise research.

Here at the Desert Tortoise Conservation Center in Las Vegas, spring is standing on our doorstep, and we’re all preparing for the start of a new field season. Our research team is getting ready to embark on some new projects here on site, one of which required us to fix up some old tortoise pens that had fallen into disrepair over the past 10 to 15 years. This was a HUGE undertaking and one that would have taken me months of digging artificial burrows and fencing ditches as well as updating and fixing the fences for over 20 100-foot-long pens. A couple of months ago I was beginning to wonder how I was ever going to get it all done and if we’d have anywhere to put our tortoises in the spring. But the world works in mysterious ways, and just in the last month we’ve had some amazing volunteers lend a hand.

Members of the Nevada Conservation Corps after two days of fixing fences in our experimental tortoise pens.

Troop 336 with the Boy Scouts of America, Las Vegas Area Council, led by Cory Chatterton, some members of the Nevada Conservation Corps, and one of our long-term volunteers, Simon Madill, came to my rescue. Nearly 40 people came out over several days, and after some long hours of swinging shovels and pick axes in the desert sun and hours of cutting and tying up fencing, we have finally finished 20 tortoise pens!

All the enthusiasm and hard work of our volunteers mean that this spring we are able to start our tortoise behavior study. I am hopeful that the things we learn will help to improve our future reintroductions of animals back into the wild.

Jennifer Germano is a postdoctoral researcher at the San Diego Zoo Desert Tortoise Conservation Center. Read her previous post, Tortoises and Their Amazing Feats.


Do Tortoises Wear Shower Caps?

As a San Diego Zoo Global researcher based at our Desert Tortoise Conservation Center (DTCC) in Las Vegas, one of the things that really inspires my belief that the desert tortoise has a chance of surviving the threat of extinction is the interest it garners from completely uninvolved individuals. In the far northeast region of the country (read: Massachusetts), a children’s literature author (fine, she’s my mother), who had never heard of the desert tortoise until I joined the DTCC team, became inspired to help save it. Her contribution is a poem highlighting the trials and tribulations of being a highly sought-after pet in the Las Vegas area.

The idea came about as I was explaining to her that we recommend that people who call the Pet Desert Tortoise Hotline place a tortoise to be picked up in a box in a temperature-controlled room, such as the bathroom. I would like to share her poem in this forum for tortoise fans to read because it is both highly entertaining and accurate!

Do Tortoises Wear Shower Caps?

by R. G. Gokool

I found a tortoise in my bathroom and asked,

“Do tortoises wear shower caps?”

He replied, “Not at all,

For it could slip off, and I could fall.”

“Your shell is so pale,

Would you like some polish, or some glitter on it and your nails?”

“Most certainly not, I use my shell to protect me when it’s hot,

And to hide from my enemy,

Not to stand out and say, ‘come and get me.’”

“Would you like to come with me to the parking lot?”

“No, I’ve been there before and had to withdraw into my hump,

As people tried to use me for a speed bump.”

“Are you hungry? Would you like some dog food or monkey chow?”

“No, no way, no how!

I’m a desert animal, not a mammal,

I like cactus fruit, fevertail, and native grasses.

Not food that gives me lumps and makes me gaseous.”

“Can I use you for a stepstool?”

“No, you can break my shell, and that would be cruel.”

“Would you like to go for a swim?

We can go to the pool and jump right in.”

“No, I come from the desert, nice and hot.

Not from the briny deep

Where all the sea turtles sleep.”

“Would you like to meet my dog, Spot?”

“Certainly not!

“He may be cute, but not too bright,

He’ll chew my leg off in one bite!”

“Can I give you and your hatchlings to my friend?”

“If you do, you’ll find it’s illegal and you’ll pay a fine in the end.”

“Can I take you home and make you mine?”

“If you do, you’ll have to pay a $10,000 fine.”

“Can I pick you up and give you a hug?”

“No, ‘cause then I would pee,

And there are no plants for me

To get water to keep hydrated, so you see.”

“Can I put you in my fish tank indoors?”

“No, ‘cause I live outside. I didn’t come from a pet store.”

If you see a tortoise from your car,

Just admire him from afar.

Do not be sad if he doesn’t wave,

For he’s not that friendly a fellow,

He just wants to be left alone in his burrow.

Larisa Gokool is a research associate at the San Diego Zoo Desert Tortoise Conservation Center. Read her previous post, Bacteria, Viruses, and Disease, Oh My!