Amphibians are named for the fact that they spend part of their life in the water and part on the land. But not all amphibious animals are amphibians, and not all amphibians live the amphibious lifestyle. Some amphibians live in water their whole lives, and some never live in water at all!
The class Amphibia includes three orders of extant animals, the Caecilians (order Gymnophiona), the Frogs and Toads (order Anura), and the Salamanders and Newts (order Caudata). Texans aren’t very likely to be familiar with the caecilians since these fossorial, legless amphibians are restricted to tropical areas around the globe. They look rather like a big earthworm. The closest populations of caecilians to us in Central Texas are over 700 miles south in Tropical Mexico (unless you count the specimens in our San Antonio Zoo).
But we do have Anurans (frogs/toads) and Caudates (salamanders) here in Central Texas.
SOME SAY I’M THIN SKINNED
A lot of Bexar County residents and visitors may never see our amphibian neighbors. That is because amphibians have thin permeable skins that can lose water very easily. In our dry climate, amphibians must restrict their activity to wet areas or during wet periods. They are also more likely to be active at night when temperatures are cooler. And because their eggs don’t have a shell or the extra embryonic membranes that reptiles, birds, and some mammals have, amphibian eggs dry out very easily and must be laid in water or wet areas.
EAST MEETS WEST MEETS SOUTH
Bexar County is a meeting point in the distribution of many eastern, western and southern plants and animals. In the amphibians, we get both Eastern and Western Narrow-mouthed Toads. We have both Southern and Rio Grande Leopard Frogs. Just south of Bexar County, we come across the Sheep Frog, a tropical species that occurs in Mexico and Central America, living side by side with the Woodhouse’s Toad that ranges up to the prairies of the Canadian border.
A FROG BY ANY OTHER NAME
When is a frog a frog, and a toad a toad? Some people like to use the rule that frogs have smooth skin and live in water while toads have dry, warty skin and live on land. But in fact, some of our local frogs have relatively warty skin, some don’t live in water, and our Narrow-mouthed Toads are smooth-skinned.
The terms frog and toad are just terms that were originally applied to different families of Anurans. But even that rule doesn’t hold true. For example, our Sheep Frog from south Texas is most closely related to the Narrow-mouthed Toads.
THOSE OTHER AMPHIBIANS – THE SALAMANDERS
It often comes as a surprise to many Central Texans that we have salamanders!
East of the Balcones Escarpment, there is the Small-mouthed Salamander (Ambystoma texanum). But this is a salamander of the mesic pine and oak woodlands of the east-central US and is very rarely found in Bexar County anymore.
In the Edwards’ Plateau’s wet canyons, we have a salamander that is still doing fine, the White-throated Slimy Salamander (Plethodon albagula).
SECRETS UNDER OUR FEET
When people think of salamander diversity, they likely think of the Appalachian Mountains or maybe the Pacific Northwest. But we in Central Texas live at the edge of one of the great salamander diversity hotspots. Our local salamander stars are not very well known because they are restricted to springs and caves of the Hill Country and are rarely seen by most residents.
There are famous examples of this diversity, such as the San Marcos Salamander (Eurycea nana) or the Barton Springs Salamander (Eurycea sosorum) in Austin, but we have several closer to home.
- The Texas Salamander (Eurycea neotenes) was first discovered in a spring 5 miles north of Helotes in Bexar County. Its entire range is restricted to northern Bexar and southern Kendall Counties.
- Just west of Bexar county we come across the Valdina Farms Salamander (Eurycea troglodytes), originally described from the Valdina Farms in central Medina county.
- At the junction of Bexar, Comal and Kendall Counties, we find the troglodytic Cascade Caverns Salamander (Eurycea latitans).
- Then there are several other species that haven’t even been formally described scientifically, such as the Comal Springs Salamander (Eurycea sp.) in the middle of Landa Park in New Braunfels!
- Maybe the most mysterious local salamander is the Blanco Blind Salamander (Eurycea robusta). This unique salamander was discovered in 1951 by a group drilling for water in a streambed in Hays county. A total of four large, pale blind salamander specimens came up out of the underground spring! The workers put them aside in a bucket of water, and three were eaten by a heron. The remaining specimen was preserved and is currently the only known specimen of this species. It has never been seen again despite many attempts to find its underground cave/spring, but it’s down there somewhere.
We all remember the standard amphibian life cycle from high school biology. Amphibians move to ponds to breed, lay eggs in the water. The larvae hatch and live as aquatic tadpoles until they metamorphose into adult amphibians that live on land. But some of our Central Texas Amphibians didn’t read that book.
- frogs that have direct development lay their eggs on land and hatch into tiny frogs.
- salamanders that never metamorphose and live their whole lives in the water.
- salamanders that live their entire lives on land and never have an aquatic stage.
IT’S A BIRD, IT’S A PLANE, IT’S A FROG, IT’S A TOAD…
One of the widely appreciated traits of the Anurans is their songs. While not as melodic as the songs of some of our feathered neighbors, their serenades on a warm rainy night are a big part of our experience of the natural world. And unlike in some more northerly regions where it is a sign of spring, we get to enjoy these songs on wet nights throughout the year.
We have winter breeders like the Strecker’s Chorus Frogs with their metallic whistle, fall and spring breeders like the chuckling Southern Leopard Frogs, and the boys of summer like the whistled trill of the Cope’s Gray Treefrog.
Probably the most often heard of the local frog calls are the “click, click, clicks” of Blanchard’s Cricket Frogs (Acris blanchardi). This species will call day or night from along rivers, streams, or farm ponds. Its call sounds like two pebbles being clicked together.
Another familiar call in our area is the long trill of the Gulf Coast Toad (Incilius nebulifer). On any warm night in spring and early summer, this long whistled trill can be heard anywhere there is some water, even in the middle of suburban backyards.
Another common group of suburban frogs in our area are the Chirping Frogs in the genus Eleutherodactylus. They are often assumed to be crickets or even night-calling birds when they call in backyards on wet nights. And since these species breed away from water, people often hear the call and figure it couldn’t be a frog!
The two species we have are the native Cliff Chirping Frog (Eleutherodactylus marnockii) of the canyons in the Hill Country and the introduced Rio Grande Chirping Frog (Eleutherodactylus cystignathoides) that was brought to our area in houseplants from the Rio Grande Valley of Texas. Their calls are very similar sounding, only differing slightly in pitch because the Cliff Chirper is bigger. They make a series of high pitched “chirps” interspersed with an occasional trill.
As we get away from our backyards, In ponds and lakes around the county, we might hear the deep “rah-uhm” or “jug-o-rum” call of the American Bullfrog (Lithobates catesbianus).
We have two Leopard Frogs in the county, which can be tricky to tell apart visually, but their calls can help a bit.
The Southern Leopard Frog (Lithobates sphenocephalus) has a chuckling call heard during its fall-spring breeding season. It is a species that ranges widely across the Southeastern US whose range stops at the San Antonio River
West and south of the San Antonio River, we get the Rio Grande Leopard Frog (Lithobates berlandieri), which tends to breed a little later than the Southern. Its call is more of a snoring sound. You can hear the clicks of Blanchard’s Cricket Frogs calling with them in this recording.
From the reeds or bushes along the edge of ponds, we can hear the loud “wrenk, wrenk, wrenk” of the Green Treefrog (Hyla cinerea).
Here’s one calling from Fayette County again with a background of clicking Blanchards’ Cricket Frogs.
From wooded areas around ponds and flooded fields we hear the whistled trills of the Cope’s Gray Treefrog (Hyla chrysoscelis). In some parts of Texas, there is an identical-looking species, the Gray Treefrog (Hyla versicolor), but we only have the Cope’s Gray Treefrog in our area.
Flooded grassy pastures or fields, even within the city itself, are the favorite breeding ground of the tiny Spotted Chorus Frogs (Pseudacris clarkii) with their dry “fingernail over comb teeth” calls.
These little Spotted Chorus Frogs are often heard calling next to their pointy-nosed neighbor, the Western Narrow-mouthed Toad (Gastrophryne olivacea) with its piercing nasal whine.
A favorite frog species in our area would have to be the Balcones Barking Frog (Craugastor augustii). These large frogs are completely terrestrial with no tadpole stage and are found in the cracks and caves of the hill country. They are named for their loud dog-like bark which can be heard echoing in canyons of the Hill Country on rainy spring nights.
From a distance, you can really hear how dog-like the call is!
There are at least 18 species of frogs and toads in Bexar County, and their calls are pretty easy to learn. Which ones can you learn to ID? If you want to learn to identify them, you can find recordings of their calls in iNaturalist or on my frogcalls blog.
For additional material for children see Froggies by Wendy Drezek, AAMN.