Fall is a season we typically associate with changing leaves, cooling temperatures, and the natural world beginning to quiet down before the long, dormant winter months. But for some animals, the season brings new life, rather than death.
And if you’re out in the woods this month, perhaps hunting mushrooms after an autumn rain, you might just run into one. The creatures I’m referring to are Missouri’s fall-breeding salamanders: the ringed salamander and the marbled salamander.
Unlike most animals, who do their procreating in the spring, these amphibians wait until temperatures have started dropping to mate. To find out why, I met up with Jacob Burkhart – a graduate student at the University of Missouri who studies these two species.
"So the ringed salamanders just bred across most of their range," Burkhart said. "I was able to find some that bred like just last week during the rains that came through." According to Burkhart researchers think some salamanders have evolved to breed in the fall for the same reason that spurs most evolutionary developments: competitive advantage.
"If you have a fall-breeding salamander, they are able to get to a larger body size before the spring-breeders come in," Burkhart explained. "So then those fall-breeders can actually prey upon the other species of amphibians that are breeding in the spring."
By the time winter sets in, it is too cold for the fall-breeding salamanders’ larvae to develop much, but even a month or two of extra growth in the autumn can give them a valuable edge. But Burkhart’s research focuses specifically on what happens to these salamanders after they metamorphose and leave their ponds in the spring. "From metamorphosis until they come back to breed, we don’t really know much about where they go," he said. "Using genetic tools, we can try to estimate how they move across a landscape"
After dispersing into the woods, the salamanders mainly stay in one place, until it’s time to breed. Marbled salamanders and ringed salamanders belong to the genus Ambystoma – known commonly as “mole salamanders.” As the name implies, these salamanders typically live in burrows underground, and the best chance you have at seeing one is during mating season.
Burkhart said, "If you go out at night, about an hour after dark, and cruise the roads slowly in areas where you know there are ponds, you can find them pretty easily."
Mole salamanders’ sedentary lifestyles make them relatively low maintenance to keep in captivity, say, as a classroom pet. That’s exactly where I found one, in a science classroom at the Columbia Independent School.
"I have a couple salamanders in here: I’ve got an axolotl named Polly and a spotted salamander named Edwin," science teacher Christina Moore told me. Moore works with 6th and 8th graders at the school and explained that, "Edwin, the baby spotted salamander, she gets a worm or two that is cut up by one of the students, and then we have to make sure that she has water in her habitat as well."
As a mole salamander, Edwin spends most of her time burrowed in the substrate of her container. "Edwin just kind of hides out the entire time. They always want to see her, so it’s a big treat when we get to see Edwin," Moore said.
Moore says Edwin, and her other classroom animals help to get her students interested in nature, and she tells them how they can look for other salamanders like Edwin out in the woods. "Just seeing it in a classroom setting makes them more familiar with the world around them and just willing to try things." Moore added, "That’s one of my goals as a teacher is for my students just to try things and take risks."
Salamanders in particular, perhaps because of how uncommon a sight they can be, seem to attract particular curiosity, even from researchers like Burkhart who have seen thousands. "Even still, I still get excited every time I see one," he said. "They’re just really neat creatures to see. I never know when there’s going to be one under a log so it’s always exciting or surprising to find one. "