Freshwater Turtles from the upper San Saba River
Carl J. Franklin
From May to August 2009 I conducted several visits to a study site in Central Texas. The purpose of the study is to gather baseline data regarding the relative abundance of freshwater turtles in Texas. Several other institutions across Texas are also currently committed to freshwater turtle research and are undertaking similar field studies in other parts of Texas. Support for field work was provided by Texas Parks and Wildlife and the University of Texas at Arlington. The turtles captured in this study were measured, weighed, marked, photographed and released. The field site is interesting because of its overall pristine quality and intact turtle populations that have not been exposed to commercial collecting. Because of this no specific locality data regarding content herein will be provided.
Freshwater turtles occupy various habitats. However, most rarely have the opportunity to view them because they are underwater! These aquascapes are vital not only for the lives of turtles, but for the overall health of the river.
Mexican lilies Nymphaea mexicana
The exaggerated arch on the carapace of this female Texas map turtle is due to a spinal deformity called Kyphophis. This condition has been documented in several species of turtles. However, this is the first documentation of the condition among Texas map turtles. From her age and appearance this turtle indicated that she led a healthy and active life despite any aberrant spinal formations.
This is the skull of an old adult female Texas map turtle. Her shell was found nearby and no signs of predation were detected. Her shell length (20 cm) was 1.4 cm shy of the record length for the species. her size and wide skull indicate that she lived a long life and even suggest that she may have died from old age.
Unbothered by my presence, this female moved along at a leisurely pace while providing a ferry service to a blue damselfly.
This male Texas map turtle is spending a carefree morning in a picturesque stream grazing upon snails.
Nearby this female also took advantage of the abundant snails and had breakfast amid idyllic scenery.
Although found throughout several habitats in their range Texas map turtles prefer moving river streams.
After being measured, marked and photographed, this female Texas map turtle decides to rest after being released.
This male Texas map turtle was photographed underwater near the outflow of a spring. The clarity of the image is a testament to the prevailing environmental conditions.
The carapace and plastron of an adult Texas river cooter (Pseudemys texana).
Texas river cooters are beautiful endemics to the Lone Star State and easily capture the enthusiasm of even the most simple minded individuals.
A notch on the upper cusp is a useful characteristic for identifying this species.
While wading through a section of river I was spotted by this turtle who upon noticing my presence took quick evasive action.
Above and below water the beauty of this species remains.
In this photo, Erick checks and baits one of the several hoop traps used during the course of the study.
No turtles were trapped at night, but some were found sleeping including this read ear slider.
The red ear slider (Trachemys scripta elegans) is native to the southern United States. Unfortunately this species has been introduced in several states and countries outside its natural range. In many instances this creates problems for native freshwater turtles. However, these turtles are still enjoyable to encounter in their native habitat.
A long way from water, but he looks as if he knows where to go. Often aquatic turtles such as this old male red ear slider are found wandering quite far from water. This specimen had just crossed a highway on an afternoon when temperatures rose above 100º.
Another close up of the old male red ear slider. Notice how the shades of time have increased the amount of melanin and much of his former emerald green and even trademark red ears have darkened.
Another mature male red ear slider. This individual bears some interesting red coloration on top of the head as well as on the ears.
With a snake-like neck the common snapping turtle reaches to the surface for a breath of fresh air.
During the course of the study snapping turtles were found in traps and moving about. Whenever they were seen they were grabbed lest they escape into a tangle of mud and vegetation.
A grip at the base of the tail and the right rear leg secure enough purchase to retrieve the struggling turtle. Securing a firm and safe grip onto the hind leg of a snapping turtle as a primary form of restraint is preferable to grabbing and holding it by the tail. Holding them by their tails can result in spinal injuries to the turtle.
Slow moving portions of the river with an overhanging bank provided an ideal habitat for common musk turtles.
Rarely found out of the water the common musk turtle (Sternotherus odoratus) was commonly seen patrolling the bottoms of rivers, streams and ponds.
Common musk turtle use their drab coloration as an effective camouflage.
Common musk turtles were commonly encountered throughout the entire study area. These specimens represented approximately 5 minutes of collecting effort.
Moments before darting for cover this Tree lizard (Urosaurus ornatus) paused just long enough for a photo.
A male Texas earless lizard (Cophosaurus texanus)
The endearing and dissuasive sides of a porcupine are both easily observed. Porcupines were encountered along the river banks quite regularly.
These calm waters deceptively concealed the bustling turtle activity.
Successful sampling turtle populations requires patience and persistence. These 12 specimens were all captured in one day in the same trap. Included in the photo are: Texas river cooter, Red ear slider, Guadalupe soft shell turtle and Texas map turtle.
Every specimen was measured, weighed, marked, photographed and released. Erick Catalan is taking the carapace measurement of a Guadalupe soft shell turtle.
If you have children then get those kids into the field and in contact with nature as soon as possible! Above is what can happen when Nintendo, Game boy and even a DSI are unplugged, turned off and exchanged for a day catching turtles on a river. Today's children are faced with a frightening amount of deprivation from contact with nature. This is not only a great experience for kids but it allows a future generation to form a health sentiment that will undoubtedly influence the future of wild places everywhere.
Caught together and placed side by side for comparison is a red ear slider (left) and Texas map turtle (right)
Here is the same pair of turtles from a dorsal perspective.
Floating or basking style traps were also used to survey turtle populations.
A reliable vehicle with 4 wheel drive was necessary for getting to and from several field sites.
Raccoons are a serious predator to turtles. The shell in the photo above is of the common musk turtle (Sternotherus odoratus) and the shell in the photograph below is the remains of a predated red ear slider.
This handsome Central Texas whip snake (Masticophis taeniatus) was an interesting find during the study.
For years shooters have used turtles for target practice. Interestingly the turtle do survive some of these injuries. This photo depicts what is very likely to be the result of an old but healed bullet wound in the middle of the back of this large female Guadalupe soft shelled turtle.
This old male red ear slider also sustained a bullet wound. However, this one was locate on the outer marginal scales.
As we were preparing to leave a trap location we happened to find this sleeping baby deer.
Like other mammals in the area (including us!) this deer hosted a number of blood thirsty ticks.
After its mother was frightened away by a passing truck this baby striped skunk was wandering alongside the road. It was carefully picked up and placed in vegetation where its siblings were waiting for their mother to return.
Cattle guards can sometimes cause unexpected mortality among turtles. This female red ear slider got stuck and was facing a fate that had fallen upon another red ear slider at the same cattle guard.
The rugged Central Texas landscape provided an interesting contrast to the aquatic setting.
Evidence of turtles leaving the water for terrestrial forays sometimes leaves very distinguishing evidence.
Texas rat snakes (Pantherophis obsoleta indheimeri) were a common occurrence in the field and on the pavement.
Occasionally turtles were encountered in surprising locations (above and below).
An albino dragonfly? Perhaps. This individual was photographed while drying its wings following its emergence from life as an aquatic naiad.
Our campsites were very basic and simple. They essentially provided a nice place to sleep at night.