A member of the group called the mole salamanders, the Spotted Salamander, Ambystoma maculatum, leads a life similar to that of those little gray mammals. They spend most of their lives alone in dark subterranean networks of mammal tunnels. Here they stalk their wily prey—earthworms and other soil invertebrates.
The big event on the spotted salamander calendar is their annual sojourn to their breeding habitat. The preferred habitat for this activity is a woodland vernal pool. The best of these hold water for much of he summer, but dry up at least during some years, thus dooming or discouraging such aquatic species as fish, bullfrogs, and snapping turtles that would eat their eggs and young.
It is on these treks to their breeding pools that we have the best opportunity to see these amphibians. They are up to 9 inches long, gray to black, and each salamander has a distinctive pattern of yellow polka dots on its back. The belly is usually pale gray, but can sometimes have light spots, as reported by one crossing guard this year.
Once in the pools, the males gather in groups called congresses. The congress at its peak can be a sphere of up to 200 undulating swimmers, yes it’s the Salamander Ball! The bottom of the pool will be speckled with spermatophores, the white packets of genetic material excreted by the males. When a female arrives and has been sufficiently stimulated by gyrating males, she and a suitor will leave the ball, and he will beckon her to follow him with his waving tail. He will lead her to his spermatophore. If she is suitably impressed, she draw it into her cloaca to fertilize her eggs. She will lay a cluster of 100 – 300 eggs attached to a stick or pond vegetation. After the eggs have been laid, courtship is over and that salamanders return to their fossorial lives. (There are many accounts of Spotted Salamander courtship, and the details don’t always match. According to some, females select spermatophores at random. I suggest that you visit a pool on the night after salamander migration and see for yourself.)
The young salamanders wriggle free of their jelly coating after a month or two. The warmer the water temperature, the sooner they hatch, but the warmer the temperature, the sooner the pond will dry up. Each year it is a race with the sun. The larval salamanders have feathery gills and very soon develop legs, but it takes a few more months for them to be ready to join their kind on land. Many vernal pools will dry before this metamorphosis can be completed. Fortunately, Spotted Salamanders can live 20 years, so the adults might have many opportunities to reproduce.
The first salamander to head for the pools in these parts is likely to be the Jefferson salamander, so if you’re going out to check your site when it seems just a bit too cool for spotted salamanders to be out yet, watch for these guys. More slender than the spotted salamander, the Jefferson seldom exceeds seven inches in length. The snout appears long when compared to the broad snout of the spotted salamander. The body color is dark gray to brown, and the sides and belly usually have pale blue flecking. This flecking can disappear as salamanders age.
Mind you, it’s not usually difficult to tell Jefferson salamanders from spotted salamanders. It can be difficult to tell the Jefferson from the blue-spotted. Blue spotted salamanders have larger blue flecks that appear on their backs and legs, as well as their sides and bellies. They are the smallest of our three mole salamanders. You would find it easy to distinguish the three, but Jeffersons and blue-spotted hybridize, creating a blending of the characteristics of the two. Read more about these hybrids here.
Jefferson salamanders are rare throughout their range, which includes much of eastern North America, from Kentucky to southern Labrador. In Vermont they are listed as a “species of special concern,” and are not seen at many of our crossing sites.
We are especially interested in getting photos of any Jefferson or blue-spotted salamanders you find at your site this year. Please read the article on taking photos and help to document the distribution of these uncommon creatures.
Blue-spotteds are significantly smaller than spotteds, measuring only 4 – 5 inches in length, and a Windham County rarity (so perhaps I can be excused). They have bright blue to white freckles on a bluish-gray to black background. These spots are sprinkled liberally and randomly over the whole salamander. The pale flecks on a Jefferson’s tend to be concentrated on the sides and belly.
Jefferson’s and Blue-Spotteds’ ranges overlap, and where they do hybrids are often more common than either pure species. These two species and their hybrids form a group we call Jefferson’s Complex. Most sensible sexually reproducing species have chromosomes that are arranged in matching pairs—a condition called diploidy. Eggs and sperm each contain one set of chromosomes (haploid). These chromosomes merge when an egg is fertilized and a new diploid life begins. Many of the hybrids, however, are triploid, tetraploid, or even pentaploid. Most of the hybrids are females. These hybrids can reproduce by gynogenesis. This means that the egg requires a male sex cell to become activated, but it does not fertilize the egg. When the female produces eggs, the numbers of chromosomes are not reduced. The egg develops into a clone of the mother.
However, some research indicates that gynogenesis in these salamanders is temperature dependent. When temperatures are 60°F or warmer, the egg will be fertilized, and the male chromosome will be added to the female’s (making the offspring of a diploid female a triploid, etc.) If water temperatures are cooler than 41°F, reproduction will be through gynogenesis.
So, what do we call those speckled salamanders that don’t have yellow spots? Nearly all of them in our region look more like Jefferson’s than Blue-Spotteds, and since we can’t tell without checking the DNA, we consider them Jefferson’s Complex. If you find one speckled like the one in the picture above, though, it might be the less common Blue-Spotted, or a hybrid in which blue-spotted genes are more numerous. If you see one on a crossing night, record it as blue-spotted, and please take a picture!
Four -Toed Salamander
The four-toed salamander has been reported at only one of our crossing sites, but perhaps that is only because we haven’t known what to look for. The four-toed is the least-known salamander in the state, partly because it doesn’t get out much, and partly because when it does, the diminutive four-toed is a good deal less conspicuous than the spotted salamander There are places in Vermont, however, where four-toeds are reported on amphibian crossing nights. They are not moving to vernal pools, but from drier upland overwintering sites to their summer homes in clumps of damp sphagnm moss in swamps and bogs.
These salamanders lay their eggs on the underside of these moist tussocks in a place where the hatchlings will drop into water when the big moment comes. It is possible that these salamanders could show up at our crossing sites where amphibians are moving to wetlands with sphagnum moss. Remember to bring your camera when you go out so you can document any four-toed sightings!
Here’s what to look for:
- TINY, 2 – 3.5 inches long
- Reddish-brown back
- Pattern”etched” into back
- 4 toes on front and hind feet (most salamanders have 5 toes on hind feet)
- Tiny legs, stubby toes
- Slender body
- Belly white with big black speckles
The belly feature is the one that is the easiest to use to identify four-toed salamanders
It is the Spotted Salamanders, those mysterious recluses in their polka dotted suits, that steal the show on Big Night, but they are not the only amphibians who benefit from our help. Wood Frogs, another solitary woodland species, also gather once a year in vernal pools for an interlude of intensive intimacy. Like the salamanders, the risks they face to mate increase when the journey to their pools takes them across busy roads.
On April 3, with temperatures hovering close to 40° F, and with a light sprinkle of rain settling on top of dry soil, it seemed unlikely that many salamanders would be lured to their pools, but I knew my site would be hopping—Wood Frogs are less discriminating about temperature than salamanders. In fact one of their charms is how very indiscriminate they can be. My site, Depot Road in Williamsville, is the biggest Wood Frog crossing site that we have identified.
Sure enough, Ki, Shane, Stewart and I had our hands full escorting frogs to safety.
The more enthusiastic of the male frogs were easy to spot. They perched on the asphalt in an upright posture. In dark bandit masks, they looked like miniature highwaymen hoping to plunder a stagecoach before retiring to the tavern for a night of carnal revelry. Most put up little resistance to the transportation we offered.
Other frogs, spent from their travels (after months of hibernation), had no energy left for good posture. They felt like empty frog sacks as we scooped them up. I hoped the pool party would rejuvenate them. Some of these seemed grateful, not so much for the lift across the road, but for a sheltered spot to rest. They hunkered into the warmth of my hand and seemed loath to hop on.
Soon the pond quacked with the mating calls of the males who had arrived. As we walked the road, we would sometimes hear the cluck of a frog warming up for his performance as he hopped through the woods. A few offered a little “kkRRruuK” when I picked them up. Still others were so eager to mate they gripped my fingers, and I had to pluck them off to set them free once we crossed the road. The gravid females seemed more practical. They hopped slowly but steadily. Their sides swelled with the eggs they carried to the nurturing waters of the pond. One stalwart female hopped along with a male already clinging to her back.
I thought I would leave at 10:30 when the rest of the team headed home. As all crossing guards can attest, it is hard to go home when the amphibians are still coming. “Just a few more,” I thought, as the rain began splashing the road with more vigor. I don’t know if it was the increase in the volume of rain or the reduced activity of the human patrols, but in a moment I found myself in the midst of a festival of frogs. They flowed down the banks and into the road, a stream of amphibious life. I couldn’t begin to keep the road clear, so I was very grateful that the couple of cars that passed through the site were driven by sympathetic folk who were happy to have a path made through the Wood Frog parade.
We saw just three spotted salamanders that night, but I was not disappointed. I knew we had helped over 400 frogs reach their breeding pool in safety. While there we managed to nearly eliminate mortality.
Although I felt disturbed by the few frogs that did not make it across the road, visions of charming Wood Frogs hopped through my mind the whole way home. —Patti Smith
As the spring amphibian migration season progresses, the stalwart toad hops onto the scene. Like frogs and salamanders, the American Toad, Bufo americanus, is seeking semi-permanent, fish-free, still water for breeding. Unlike the other species, the toad is likely to linger in the road along the way. Toads like to be warm, and often roads are the warmest places to be on rainy nights.
You can recognized toads by their warty hides. Especially prominent are the two parotid glands just behind the eyes. These glands secrete the milky toxin that is one of the few defensive tools in the toads’ arsenal. Only the hog-nosed snake routinely eats toads, although the garter snake will, too.
The legs are another distinguishing feature. Toads have short hind legs when compared with the frogs that leap through our crossing sites. Don’t enter a toad in a jumping contest.
I once found a toad in a basement in January and kept her until April. I enjoyed watching her feed. When she spotted her quarry, she rose onto tiptoes and crept within striking distance in a very feline manner, albeit a fat dumpy feline manner. After a moment of stillness, her sticky tongue would shoot out and draw the hapless invertebrate into her mouth. If necessary, she would use her front legs to stuff the meal in. Her eyes would close and roll back in her skull as she swallowed.
When the toad chorus began, I took her to the pond and sent her off in search of the mate of her dreams.
A toad chorus is a marvelous sound. Their sustained musical trills intertwine in wild harmonies. It is fitting that the oft ridiculed toad should produce the loveliest of our amphibian music.
Toad eggs are easy to recognize. They appear in long double strands in shallow water. If the water is warm, the tadpoles will wriggle free in as few as 3 days. Each female can lay 4000 to 8000 eggs! It is no wonder that toads are one of the most familiar amphibians. Their penchant for lingering in roadways could change that, though.
Note: Be sure to wash your hands when you’ve been helping toads. They won’t give you warts, but their skin secretions can irritate skin and eyes.