Salamanders

Tim Iverson

(8/2016) There are over 500 different species of salamanders worldwide. 171 of those species call North America home, and 21 can be found in Maryland. The smallest salamander here is the Four-Toed Salamander, which is about three inches long maximum. The largest species in Maryland is the Eastern Hellbender and can be up to two feet long and up to two pounds. Despite the foreboding name the Hellbender is completely harmless, and found primarily in Garrett County. Due mainly to habitat loss and degradation the Eastern Hellbender is listed as endangered in the state of Maryland, and threatened throughout the rest of its native range in the US.

Salamanders start life as an egg in a shallow calm pool of water. The eggs are laid in a clump and are coated in a clear jelly, much like frog eggs. Their early life resembles the life cycle of frogs closely. Once the eggs hatch the newly born salamanders, called efts, look a lot like tadpoles. They’ll spend much of their time over the next few weeks swimming, eating, and growing. After a period of days or weeks, depending on the species, the young efts will grow legs and morph into their adult form.

All salamanders are carnivores, preferring mostly slow moving prey. Slugs and worms top the list of favorites. Other common foods include crickets, beetles, fish, crayfish, and other salamanders. Salamanders are a key component in the food web, and fall somewhere in the middle of the chain. They are an important predator species keeping lower rungs on the ladder in check, but also provide a valuable food source for higher levels up. Salamanders are often food for snakes, fox and other smaller forest mammals, fish, toads, frogs, and of course other salamanders!

When you’re in the middle of the food chain you have to put up a good fight, and salamanders have a few defense tricks up their collective sleeve. Many have engaged in the biological arms race of evolution. Their sensitive, yet incredible, skin is coated in a slime which can be toxic and usually tastes extremely foul. In some cases salamanders can survive for up to 30 minutes in the stomach of a predator and can either be thrown up or crawl back out of the mouth in the event of the predator’s death. Salamanders will either sport bright lively colors to warn predators of these toxic chemicals or will utilize subtle earth colors in an attempt to camouflage within the environment. A last ditch defence is sometimes a small bodily sacrifice. It’s better to lose and regrow a tail than to be eaten. A new tail can regenerate within a few weeks without any serious consequence or harm to the salamander.

Salamanders have incredible skin, it serves as a lifeline for them in multiple ways. A slime or mucous coats the skin generated by glands within the body. This mucous provides a defense against predators by containing toxins that taste bad and can potentially kill a predator when ingested. The slime is also quite slippery making them hard to catch by hungry predators or curious human hands alike. This mucous coating also protects against bacterial and fungal infection keeping salamanders healthy. Like other reptiles salamanders will shed their skin periodically, and this can serve as a meal for them providing additional energy and nutrition. The coating is important for heat regulation and breathing ability. Some salamanders have lungs and can breathe through their mouths. Others have gills and breathe similarly to fish. Othersl breathe straight through their skin and need their skin to be moist to do this, which is possible because of the permanent slime covering.

Salamanders can be either terrestrial, aquatic, or both. No matter the case in habitat they absolutely require a damp environment with access to a regular water source. This is absolutely necessary to keep their unique skin moist. Salamanders are nocturnal and can generally be found hiding under rocks, logs, and leaf substrate on a forest floor during the daylight hours. Their skin is highly sensitive and because of their dependence on water scientists view salamanders as an important indicator species in water or stream ecology.

Researchers with the Maryland Biological Stream Survey are reporting fewer salamanders found every year. Numbers are in decline and it’s likely due to environmental degradation and increased runoff pollution ending up in streams. Salamanders have permeable skin which allows water to pass through. Unfortunately it also takes in pollutants like chemicals and toxic gases found within the water, essentially making salamanders like a sponge. Pollutants can come from chemical treatments by agribusiness and homeowners. They also come from increased urban development causing runoff to dump straight into streams. Without sufficient riverside buffer zones to filter runoff amphibian eggs suffer and may be too damaged to support the life within. Adults are also affected because of the permeability of their skin, and if the environment becomes too toxic they will perish too. By planting rain gardens or volunteering to plant trees and other plants in riparian buffer zones you can reduce damage created by runoff. The Maryland Department of Natural Resources also hosts an annual citizen science volunteer project called "Stream Waders." Stream Waders’ primary goals are research, education, and stewardship through the efforts of volunteers. Volunteers collect samples of water and aquatic invertebrate species. These samples allow scientists to get a snapshot of the overall water quality and see how well a stream is doing.

For over 350 million years salamanders have been able to thrive in and around streams. Able to elusively carve themselves a niche on the evolutionary ladder. These fascinating little creatures have developed some interesting ways to adapt and survive. With these adaptations they’ll hopefully be able to see another 350 million years.