An Honorable Herpetologist

slender salamander  

I was sad to learn of the recent passing of the great herpetologist Robert C. Stebbins.  Long before I met him, I was fascinated with his descriptive and beautifully illustrated field guides to western amphibians and reptiles.  Matthew Bettelheim has posted information about Dr. Stebbins here and is inviting people to share their memories of him. The commentary there will be worth visiting in the next few weeks as Dr. Stebbins encouraged so many people to discover the fascinating world of reptiles and amphibians.  My thanks to his family, colleagues and friends for sharing Dr. Stebbins and his legacy.

Tonight, I think I will share some photos of my favorite times with California herps to say my goodbye. So many scaly and slimy adventures of learning and delight.

Call of the Ponds

In the frenzy of breeding, some amphibians get confused.

The frogs, toads and newts are heading to the ponds and creeks for their annual breeding. With all the rain we've been getting, these are happy herps. Now is a good time to visit ponds and creeks to witness this seasonal event.

The skewed distribution of rain in California means that some ponds and creeks are wet only in the winter and spring months. If there is rain. As a result, many California amphibians only visit the wet areas for a short period during their hectic breeding season and that is the time you are most likely to see and hear them. Not only is the water a window into their reproductive rituals, but in their frenzy to complete their duties before the rain ends, they seem less sensitive to human curiosity.

A male aquatic-phase newt shows off his black nuptial toes.

The male amphibians usually splash down first and undergo some type of physical transformation to prepare for their upcoming adventures. Male California newts develop smooth skin, swollen limbs and streamlined tails for navigating to their sweethearts in water. They get rough, black tips on their toes, called nuptial pads, to grip the female during mating.

Small in size, the male treefrog pumps a bellow below his chin so that his call can be heard from long distances by female frogs (and people too).

From every pond, creek, ditch, cattle trough and puddle at the Dipper Ranch right now, comes the chorus of male treefrogs. Their two-note (kreek-ik) call, which advertises their fitness for breeding to the female treefrogs, is mostly heard on warm nights, but also on rainy or overcast days. At the height of the breeding season, the treefrogs can't seem to resist calling even during a sunny day. The treefrog chorus will suddenly fall silent as you approach a pond's edge, but soon one frog will start trilling, and not to be outcompeted, the others will quickly join in.

Treefrogs in amplexus. As the female (bottom) releases eggs, the male releases sperm for external fertilization.

Newts in amplexus. Sometimes extra males join in.

Fertilization of eggs is facilitated by amplexus, wherein the male embraces the female from above or behind. In the newts, amplexus occurs as the pair swims slowly and gracefully together around the pond. Surely, this is one of the most peaceful rites of springs to be witnessed at the edge of a pond.

A female newt grasps pond vegetation as an egg mass emerges between her rear legs. Another newt egg mass floats in the water below her belly.

Eggs of each of the amphibian species can be distinguished by their different shapes and sizes. See links below for photos and descriptions. It's worth returning to the ponds and creeks in the next few weeks to witness the hatching of tadpoles and larvae and their transformation into tiny land-hardy frogs and newts.

So gather the family and go visit a pond or stream. Walk right up to the edge of the pond or into shallow waters and squat down to watch the aquatic play. Some activities you might try during your pond-gazing visits:

• Can you name the different types of frogs, toads and newts?
• Do you hear different frog calls?
  
• Can you see the difference between the males and the females?
• Can you see different types of eggs?
• What are the amphibians eating in the pond?

For clues, see the links below for more information and photos.

• King of the Pond
• Raining for the Homeless
• Frog Calls
• Night Life at the Ponds
  
• Big Changes in Frogtown
• 256 Newts
• Egg of Newt
  
• Tadpoles Compared
• Frog Alert
• California Herps website
  

Peering at you peering at him.

Names of amphibians mentioned in this posting:

• Sierran treefrog, Pseudacris sierra - formerly called Pacific Treefrog, Pacific chorus frog, Hyla regilla or Pseudacris regilla.
• California toad - Bufo boreas halophilus
• California red-legged frog, Rana draytonii
• Coast range newt, Taricha torosa torosa

Toadlet, Finally

A tadpole finally transmogrified into a tiny toad in the kitchen tank today. Here he sits peacefully in his own bubble atop an algae island.

A little toad history - I first spotted toad eggs in the Newt Pond on the ranch on March 18th. On April 15th, the Newt Pond was alive with thousands of toad tadpoles. Several sources state that the California toad takes about 8 weeks from eggs to first toad-hood, but I only saw toad tadpoles with no legs and no mini-toads around the rapidly shrinking pond in May. By late May, I was concerned that the the tadpoles would not make it out before the Newt Pond disappeared, so I collected a few toad and treefrog tadpoles and placed them in an aquarium in my kitchen. The Newt Pond was completely dry by June 7th.

This guy took 26 weeks to grow up. That is a lot longer than 8 weeks. It could have been differences in the water temperatures or food supply in the kitchen tank. Although hard to tell in this photo, he has the distinct yellow toad line down his back and lots of warts. Over the next few days, I will watch to see if any other toadlets appear in the kitchen tank and try to get better photos.

This toadlet is barely the size of my pinky fingernail. Interestingly, Friday night I saw a figure scrambling across the driveway when I came home after dark. I stopped the car and watched a larger-than-fist-size California toad hop across the drive and up a steep bank. I don't know how long it takes a toad to get that big, but that's a lot of bug-eating.

California toad, Bufo boreas halophilus

Big Changes in Frog Town

--- Sierran treefrog tadpole with tiny leg developing in the tail membrane. ---

The Pacific treefrog tadpoles spent the summer transforming into mini-frogs. Meanwhile, their name changed to Sierran treefrog.

--- Big tail, small legs at Plum Pond, May 20th. ---

A treefrog tadpole completes its aquatic life from egg through tadpole to small frog in about three months - longer, if water temperatures are cool. Depending on when the eggs where originally laid, treefrog tadpoles typically metamorphose in California from June to late August.

-- The Plum Pond on May 11th with visiting black cows. ---

As the summer flies by, the Plum Pond shrinks but still gets enough spring seepage that it does not completely dry up. Depending on their seasonal rotation, the cattle may drink from this and other ranch ponds as late as mid-July. Frogs are plentiful at the Plum Pond, although hard to find on hot days.

--- The Newt Pond was shallow and muddy on May 10th. ---

The Newt Pond dries up every year, sometimes filling and drying several times in the year. This year it dried up for good by June 7th which is 56 days later than last year. Earlier, in anticipation of its annual demise, I collected a few treefrog and toad tadpoles from the Newt Pond and have been raising them in a fish tank. Because of the cooler conditions in my kitchen, the tank tadpoles are developing more slowly than those in the Plum Pond.

--- On June 13th in the kitchen tank, most of the treefrog tadpoles (top three) had legs,
but the California toad tadpole (bottom) did not. ---

In late May, the Plum Pond had treefrog tadpoles at several stages of development swimming about the warm, shallow water eating mostly algae. The youngest tadpoles had small rear limbs pushing out of the base of their tails. Frogs with larger legs used them to navigate through tangled vegetation.

--- Treefrog tadpole with muscular rear legs at the Plum Pond, May 20th. ---

On some Plum Pond tadpoles, the pair of front legs had burst out of a fold of skin in front of the belly. At this point, the tadpole is about to come out of the water and there are numerous internal changes also occurring. Its tail gets less finlike and more stump-like as it is adsorbed into the body. Lungs develop. The tadpole stops eating for a short time while its sucking mouth converts to jaws and its digestive system is converting from one that processes vegetable matter to one that breaks down animal matter.

--- Suction mouth and big, shiny belly of a tadpole in the kitchen tank on June 13th;
it also has new rear legs and soon the front legs will push through the bulge in front of the belly. ---

--- All 4 legs but still packing a stumpy tail at the Plum Pond, May 20th. ---

--- In the kitchen tank on June 26:
left - newly metamorphosed treefroglet,
right - treefrog tadpole. ---

With all 4 limbs, the metamorph creeps out of the water, although it quickly leaps back in whenever disturbed. Over the next 5 or so days, the stumpy tail disappears completely. Initially, the froglet looks dark and skeletal, much smaller than the tadpole of a few days ago, probably due to its temporary fasting during metamorphosis.

--- New treefrog at the Plum Pond on July 13th and only 3/8" from nose to rump. ---

--- The first treefrog to metamorphose in the kitchen tank is a rich copper color. ---

The young frog will use the suction-like discs on its toepads to climb pond vegetation where it will sit in wait for passing prey, mostly small, flying insects. If successful at its new hunting strategy, it will fill out into the more typical frog shape.

--- Adhesive toe pads allow the treefrog to climb up many surfaces, even glass. ---

Some herpetologists have recommended reclassifying the Pacific treefrog because of differences in its body structure from the eastern treefrog, and also because of subtle differences between the populations throughout its California range, including something to do with those fancy toepads. For this blog site, I've committed to using the nomenclature and taxonomy for reptiles and amphibians as designated by the California Herps website because I think it's a good resource that stays current with the experts and particularly with field biologists working in California. While the tadpoles were transforming this summer, Gary Nafis converted to the new treefrog names on his website and I am too. See the California Herps website for more details on this name change and distribution maps.

See also:

Sierran treefrog, Pseudacris sierra - formerly called Pacific Treefrog, Pacific chorus frog, Hyla regilla or Pseudacris regilla.

California toad - Bufo boreas halophilus

Tadpoles Compared

--- California toad by Debbi Brusco ---

Here's a California toad guarding his hole from the foreclosure agents. You can tell he is a toad by the yellowish line down his back. And the warts. But how do you tell a toad tadpole? They're black commas.

Let's update the progress of the toad eggs. We originally mistook them as tangled shoestrings in the Newt Pond on March 18th. California toad eggs are black dots laid inside long, double-walled, clear jelly tubes. On March 22, we noticed the tubes had started to break apart even though the eggs were still roundish and the embryos were not developed. Toad tadpoles hatch out in 5 or 6 days by busting through the jelly tube.

<--- busted toad tubes by David Tharp ---


I am not sure why these tubes were already broken apart. My guesses are: the Newt Pond is high on a ridge, and sometimes the wind creates a fetch that agitates the shallow water and may have broken up the tubes prematurely. Curiously, we saw many tiny, white mite-like critters clustered on the jelly tubes and maybe they were breaking them up. Or maybe the hatching is spread apart by several days and some tadpoles busted out early, loosening their brethren eggs. Good thing the toads hatch out in just a few days, otherwise, I would probably come up with more theories.

<--- 'mites' on toad tubes by David Tharp ---


In any event, the hatching seemed successfully, as by April 5th, thousands of toad tadpoles were massing along the edges of the pond. The toad tadpoles start out about 6 mm long and are dark black, so black you can't make out their features.

Compare this to the Pacific treefrog tadpoles that hatch in 6 days, quickly grow to 1 cm, develop enormous tummies and are camouflaged with dark olive backs marked by black dots and a coppery underside.




<--- treefrog tadpole on left, toad tadpole on right ---

I am not sure why the toad tadpoles are so dark and obvious and the treefrog tadpoles have cryptic coloring. I carefully watched adult newts nosing about the pond vegetation in a hunting pattern and they did not snap at the black commas as they wiggled by. Adult toads have toxic, foul-tasting substances (Pickwell) in their "warts" (why dogs usually spit out toads), but I don't know if the tadpoles are so equipped. Pickwell notes that predacious water insects capture and suck the fluids from frog and toad tadpoles.

Meanwhile, the newt eggs have been developing into twitching knife-like larvae and carving out of their individual eggs and then the outer casing. A number of newt egg clusters were washed up on shore on the windy day I last visited the Newt Pond. As I tossed them back into the pond, I noticed several newtlets pop out of the floating cluster and swim away. I cheerfully shouted, "I birthed them!" and the coyote hunting rodents in the nearby meadow looked my way.

<--- newt larvae about to bust out ---


Toad and frog tadpoles are herbivores and spend their days scraping up algae and decaying matter from rocks and the pond bottom with sucking mouths and tiny teeth. Newts are carnivorous all their life, so their larvae are devouring small pond critters. I rarely see newtlets in the ponds; as carnivores, maybe they lurk in the shadows.

The toad tadpoles will metamorphize in about 8 weeks from egg laying or mid-May. Will the water in the Newt Pond last that long? It rained today, so maybe. They hop out of the pond as tiny toads 6 mm from snout to tail end, and sometimes they still have a bit of tadpole tail they carry around for awhile. The treefrog tadpoles take about 12 weeks to metamophize, so that would be mid-June. Hmm, not sure if the Newt Pond is going to last that long, but treefrog eggs in the deeper Plum and Mallard Ponds will certainly have enough water to get to hopping stage.

I rarely see tadpoles of the California red-legged frog. They are larger (up to 7.5 cm long), dark brown or yellowish above, shiny pink below with white spots in a line along each side (Stebbins). From above, their eyes are closer to the centerline of the head and not along the outer edges like the treefrog. Both the red-legged frog tadpoles and the newtlets can spend over a year before they metamorphize, so they need longer-lasting ponds.

Thanks to my pond companions who provided some of these great photos and co-speculate on the mysteries of shoestrings and busted jellies. We are going to have a toad party in May if the Newt Pond lasts that long.

<---can you find the hidden treefrog tadpole?---

See also:
California toad, Bufo boreas halophilus
Pacific treefrog, Pseudacris regilla
Coast range newt, Taricha torosa torosa
California red-legged frog, Rana draytonii

Gayle Pickwell, Amphibians & Reptiles of the Pacific States, Dover Publications, 1972.
Robert C. Stebbins, Western Reptiles and Amphibians, 2003.

Toads Lay Eggs Too

After a challenging morning trying to explain the simpleness of grasslands, I introduced a like-minded associate to the Dipper Ranch ponds. While circumnavigating the Newt Pond, I was surprised to see a snarled black string in the water. I reached to pull it out when I realized it was actually the egg strands of the California toad. They look like long, clear jelly tubes filled with a double row of shiny black beads.

I occasionally see toads crossing the Dipper drive - in their shuffling toad fashion - on rainy nights. I have never seen their eggs before. One female California toad can lay over 10,000 eggs with the male helping to squeeze them out of her body and fertilizing them externally. It sounds like something out of the Willy Wonka factory.

Go outside and look around without an air of expertise. Nature may delight. One day, if I am especially humble, perhaps I will hear the chirping of the California toad, a sweet sound for this warty rambler.

See also:
California toad, Bufo boreas halophilus
Gayle Pickwell, Amphibians & Reptiles of the Pacific States, Dover Publications, 1972.