frog calls, october 2014

Frog Calls October, 2014

Frog Calls

Newsletter of Crosstimbers Connection Volume 2, No.3 f October, 2014

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During the hottest part of the summer, we planned

indoor presentations at the Fort Worth Nature

Center & Refuge (FWNCR). We avoided the heat

and drought, and everyone who came seemed to

have a good time. On July 5th, Michael gave a talk

about venomous snakes of our area, complete with

slides and a copperhead and pygmy rattlesnake for

people to see. Then, in August the presentation

covered the nonvenomous snakes of our area, and

our big, friendly bullsnake was a big hit with

everyone. Then, in September we covered frogs and

toads, bringing lots of slides and audio clips of the

distinctive calls of each species.

Also in September, we once again visited the Clear

Fork of the Trinity River in Benbrook, with Nic

Martinez as our interpreter of all the things in and

around the water. We netted several species of fish,

including green and long-ear sunfish. We also found

many crayfish, either trapped in pools or seeking

shelter in the river’s muddy bottom. The drought is

taking a toll on the river’s flow, but we made the

best of the pools of water that were still there. One

of the crayfish appears to have been a red crayfish

or “red swamp crayfish,” Procambarus clarkii, a

species that the book Texas Crawdads reports has

Events in July Through October

Field Trips & Presentations – Summer & Fall


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been seen in Dallas but not Tarrant

County (where we were). Dominic

found a tiny juvenile Texas brown

snake, and of course we saw cricket

frogs on most of the muddy banks.

Just as we had last year, we seined

up ghost shrimp and harmless water

scorpions. Nic was a never-ending source of

information about all these animals. He also

filled us in on some of the vegetation along the

banks, including the invasive water primrose

and the little widow’s tear that traps a

“teardrop” of water in the flower.

As fall arrived, we had a booth at FWNCR’s

“Monster Bash,” a celebration of the legendary goat-monster that some claimed to have seen back in

1969 around Greer Island. The fall weather was perfect, and we talked with many visitors who loved the

bullsnake and our box turtles.

A week later, our talks branched out from herps to invertebrates, with Clint King talking with people

about butterflies, moths, beetles, and other insects. He described ways of looking for and capturing

these critters with nets and, for some, using lights to attract them at night. He also set up a light outside

the Hardwicke Interpretive Center to see what might be drawn to the light. We took participants on a

short walk after the talk, looking for invertebrates in the gathering darkness. We saw a rare black witch

moth right at the door to the center, and then found other things in the surrounding area, including a

wheel bug and a centipede.

Field Trips & Presentations

Above: red crayfish; left: sunfish; below: water primrose


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These events have been a great deal of fun for

us to provide, and we believe those who have

attended have had a great time. We look

forward to continuing our field trips and

presentations – Michael will present about turtles

in November, and Clint will talk about arachnids

(spiders and their kin) in December.

Below: Clint and others, checking for insects attracted to the light; right: the black witch moth

Field Trips & Presentations

November 1, 2 to 3pm: Turt les of North Texas - Several species of turtles are common in north Texas, and they get some protection from their bony shells. Come find out whether that shell still gives them the protection that they need in the modern world. We’ll look at a couple of native turtles close up, and then if weather permits we’ll take a walk to look for some turtles and other reptiles and amphibians. December 6, 2-3pm: Arachnophil ia - This program is about spiders and their kin (“arachnids”) and their interesting forms and life histories. Some spiders build webs with amazing geometric patterns. Scorpions glow blue-green when we shine a black light on them. And out in west Texas, the bizarre vinegaroon looks a little like a scorpion but instead of stinging it squirts a stream of vinegar toward anything that threatens them. Come see slides and hear stories of these amazing animals. (While Crosstimbers Connection does not charge a fee, there is an entrance fee to the nature center-see their website, www.fwnaturecenter.org)

Don’t Miss Out! Our next programs at Fort Worth Nature Center & Refuge


Our Long-Lived Turtles Dinosaurs Got Nothing on These Amazing Survivors

By Michael Smith

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Some time around 225 million years ago, give or take a few years, some very early reptiles developed armor

plates across their backs that made their day-to-day survival a little easier. Back then, at the dawn of the age of

dinosaurs, turtles got their start. They have been around ever since, watching the Brontosaurs and Tyrannosaurs

come and go, seeing sabre-toothed tigers and mastodons have their day, and keeping on going in that steady

and deliberate way that turtles have. Turtles are one of nature’s most amazing success stories.

Their shells are made of modified ribs and other skeletal parts. Imagine a backbone, ribcage, and breastbone

expanded and re-tooled to cover most of your body, and covered with a thin layer of living tissue that grows

material like fingernail. Imagine that your neck bones were so flexible that you could bend them in a tight S-curve

that would pull your head back inside this modified ribcage. You’re beginning to get the idea of what it would be

like to be a turtle.

Back in prehistory, starting in the Triassic period of the Mesozoic era, the earliest turtles arrived on the scene. One

of them, Proganochelys, would have been over three feet long and had a shell with a top (the carapace) and a

bottom (the plastron) similar to modern turtles. Proganochelys would not have been able to pull its head inside its

shell, however.

Turtles then branched out to different sizes and different habitats. For example, Archelon was a turtle that lived in

the shallow seas in parts of North America late in the age of dinosaurs. This sea turtle’s skeleton measures about

13 feet in length, making it the largest turtle that ever lived, as far as we know. It would have shared some

similarity with the modern leatherback sea turtle, with a shell that was a bony framework covered with tough,

leathery flesh.

It is also thought that Archelon lived for a very long time, which is another trait that turtles are famous for. Some

modern species of turtles live very long lives. The box turtles that we still sometimes see in north Texas may live

nearly as long as humans at times. While the ornate box turtle may generally live for between 20 and 30 years (and


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sometimes longer), the three-toed box

turtle may live longer than that. The three-

toed box turtle is a subspecies of the

eastern box turtle, and in some places the

eastern box turtle often lives more than 50

years. A few of those turtles even live to

100 or more years. The red-eared slider

that we often see in ponds and rivers can

live for over 30 years. The yellow mud

turtle, found in smaller ponds and cattle

tanks in our area, may have a similar life

span.

With old age comes wisdom, at least

sometimes, and perhaps that is the reason

that people have made up many stories of turtles as being old and very wise (as in the book, Old Turtle, by

Douglas Wood). The long lives and strength of turtles may also help explain why many creation myths feature

turtles holding up the world. In a couple of versions of Hindu mythology, a tortoise is like a foundation, for

example, supporting an elephant on which the world sits. Similar myths are found in China and Mongolia. Here in

North America, a Sioux myth was that the world was actually the shell of a giant turtle floating on the waters.

Positive qualities have been assigned to turtles in stories and literature, such as in Aesop’s fable of the Tortoise

and the Hare. In it, the turtle’s steadfast plodding determination wins against the arrogance of the faster rabbit.

In stories, turtles are slow plodders, but in real life they are sometimes faster than we might imagine. This is

especially true of semiaquatic turtles swimming in streams and ponds. With strong limbs and feet that are

somewhat webbed, the map turtles and sliders and similar turtles can put on a burst of speed. And those who

have seen sea turtles swim usually think of birds flying through the air. With their forelimbs modified as flippers,

these chelonians fly through the waters with grace and agility.

Our Long-Lived Turtles

Three-toed box turtle

Mississippi mud turtle: left – the carapace or top shell; right – the plastron or bottom shell


Crosstimbers Connection - connecting people with nature in north Texas

We take people out into the woods and prairies, looking for reptiles, amphibians, and other wildlife, learning and having fun. And we do it without charging anything (but we gladly accept contributions to keep us going). We are a nonprofit organization - please visit us on the web at: http://crosstimbersconnection.org.

Michael Smith, President Rob Denkhaus, Board Member

Debbie Dorman, Secretary Nic Martinez, Board Member

Jo Smith, Treasurer

P.O. Box 151882 h Arlington, Texas 76015

Fort Worth Nature Center & Refuge

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Our semiaquatic turtles are often seen basking on logs and branches sticking out of the water – why would they

do that? Basking in the sun has several uses for turtles. First, drying off may discourage growth of parasites or

fungus that may be picked up in the water. Second, basking exposes the turtle to the ultraviolet spectrum of

sunlight, and UV-B is necessary as part of most turtles’ metabolic activity for bone health. The primary function of

basking seems to be the regulation of the turtle’s temperature. A turtle that has pulled out of the water onto a log,

with the shell facing the sun, can raise its temperature so that it is much warmer than the water. Remember that

turtles are “cold-blooded,” meaning that they do not generate body heat like we do. Their bodies function best

within a moderate range of temperatures, and their metabolism generally increases as they get warm. And so,

they need to use their environment in order to warm up, and basking in the sun is a great way to do that.

North Texas is home to numerous turtle species. We have box turtles, the red-eared turtle, the Texas cooter and

river cooter, several mud and musk turtles, softshell turtles, the chicken turtle, and the common snapping turtle

(and occasionally we see the alligator snapping turtle in the eastern counties). Several of these are fairly common,

while others are not often seen and some seem to be declining in numbers.

In fact, around the world turtles are experiencing what many biologists are calling an extinction crisis. Of the

approximately 300 species of turtles, about one-third are at risk of becoming extinct in the next 20 years. Much of

this is due to the overuse of these animals for food and for traditional practices in Asia and other places. Even in

the United States, some populations of turtles have been wiped out because of people catching them and taking

them home as pets. Additionally, fields, marshes, and ponds often disappear because we develop them and build

things where turtles used to live. Many turtles are run over on the roads. These animals outlived the dinosaurs, but

many of them may disappear because of human activity.

There are things we can do to help turtles, such as protecting some wild places where turtles live, trying not to hit

them while we are driving on the roads, and leaving them where they are when we see one in the wild. More

information about how to help turtles is provided by the Turtle Survival Alliance (http://www.turtlesurvival.org).

You can find more information about the turtles of Texas at the Texas Turtles website

(http://www.texasturtles.org).

Our Long-Lived Turtles

frog calls, october 2014

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