At the same time that the White-tailed deer start getting frisky in the fall, another creature looking for romance is heading for the low lying depressions of the forest.
Water, temperature, length of days, or phase of the moon do not cue them, but somehow, they all know when it is time to climb out of their deep underground burrows and head for the pond.
The solitary Marbled Salamander males are on the move.
It begins in October, and these terrestrial amphibians travel great distances to reach their natal pond.
At this time of year, the ephemeral pond is most likely nothing more than a dry depression of leaves in the forest. There is no trilling or sound cue to help with location, but there are likely strong pheromones scenting the air for the imminent arrival of the females.
Ambystoma opacum differs from most other amphibians by getting a jumpstart on the breeding season. The Marbleds arrive to lay eggs from October to early December. This puts the Marbled larvae at distinct advantage over other amphibians.
By the time the Spotted Salamanders and Chorus Frogs arrive in February, the Marbled larvae will be well developed, with a hearty appetite for the miniscule larvae of their pond competitors.
The Marbled exhibits another significant difference from other salamanders. It breeds, and lays eggs, on land.
The Marbled congress can best be observed on a chilly damp night. The courtship is a sight to see. Looking on the ground, near an ephemeral pond sight, you may get to observe the ritual.
Both males and females arrive fully fueled for their few weeks above ground. They are stout creatures, a mere four inches long, but all year they have been eating voraciously to build up fat stores for this mating.
They will go weeks without eating, and so it is imperative that they have built up enough fat to survive this ordeal. Fat stores during mating season reach a level of about 15 percent, and it shows.
These handsome salamanders are plump enough to look inflated. They are boldly marked creatures, black with cross bands of silver white on the males, and more muted bands of battleship gray on the females.
The dance begins. The males do a bit of chin bumping in an indiscriminate way. They might chin bump females or males, basically anyone who looks interested. The male then performs his little dance.
Some naturalists have called it a waltz, but to my eyes it resembles more of a Merengue: not a lot of ground covered but a nice bit of salamander hip sway.
He will sometimes curl his tail in a U shaped, come hither fashion, and then he deposits a little packet of spermatophore on the ground. All the female then needs to do is squat down and pick up the sperm packet from its gelatinous base.
These guys are really ready after a year underground. The macho Marbleds don’t just deposit one packet, but may litter the leaves with ten or more packets. Testosterone levels for the males are astronomically high when the Marbleds start their pilgrimage to the dry pond.
Once the eggs are fertilized, the female then digs a tiny depression beneath a suitable log, and lays her 30 to 150 eggs. She is careful to lay the eggs at the edge of the dry pond.
When the early winter rains fill the pool, the wetting of the eggs stimulates them to hatch. A female Marbled will remain with her clutch until the rain fills the pool. You will often see her with her tail wrapped around her eggs, carefully guarding her brood from predators.
Without teeth or claws for defense, the female relies on the poison she can secrete from her tail to protect her nest from interloper salamanders, or any other predator looking for a meal.
I have seen a female wait for six weeks for the rain to arrive. She never leaves her eggs during this time, nor does she eat.
Cleverly, she does not lay her eggs at the center of the pond depression, as a brief rain might stimulate the eggs to hatch, but the water might not be sufficient to support her larvae through their full development. If the water can reach the edge of the pond, it has a better chance to be a lasting pool throughout the season. In cases of drought, the eggs become dormant until the spring.
A few short days after a heavy rain, the eggs hatch, and the feathery-gilled larvae survive on tiny zooplankton in the pool. The adult Marbleds go back to their solitary existence underground.
By Christmas, you may chance upon a single Marbled Salamander crossing the Bolin Creek trail on a cold rainy day.
Tired and thin, the Marbled Salamander slowly makes it way home to a quiet life beneath the bustle of the forest trails. Runners and bikers, trail hikers, bird watchers, and wildlife all sharing the same small patch of urban wilderness…each unaware of the other’s fascinating dance.
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