Stream Critters – Marbled Salamander

August 23, 2021
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Introduction

Marbled salamanders are marvelous critters. These thin-skinned, cold-blooded salamanders – and frogs and toads – survive winters without coats. That’s amazing. Salamanders can lose a leg or tail and grow back a completely new one. That’s incredible. Marbled salamanders spend most of their lives underground, each one alone, hidden away. But if you know where to look, you could see – and even hear¹ – a herd of these shy and individually isolated critters gathering on September evenings to start their breeding cycle. There’s no guarantee that you’ll ever see a marbled salamander but it’s a worthy goal.

Background

Marbled salamanders are amphibians. Even though they look like lizards, which are reptiles, they are NOT a kind of lizard. Salamanders have thin, moist skin. They also go through metamorphosis when changing from an aquatic larva with gills, to a young salamander with lungs. Lizards have scaly, dry skin and don’t go through major metamorphic changes.

There are 680 different kinds or species of salamanders in the world. None live in Antarctica. The southeast US is a salamander hotspot and is home to about 135 different species of salamanders. That’s 20 percent of all the kinds of salamanders in the world.  Maryland hosts 22 different species including four different species of mole salamanders. That’s the marbled salamander’s family which includes Jefferson, eastern tiger, and spotted salamanders.

Mole salamanders, as their name implies, live like moles and live most of their lives underground. They come up to the surface during the warmer months at night, to breed during September (other salamanders breed in the spring), and to go through their larval aquatic stage which takes several weeks or a few months. For that aquatic stage, they rely on vernal pools which are absolutely essential and critical habitats for them.

These sensitive habitats are not fed or drained by streams. They are fed by run-off from the surrounding land and rising groundwater. Vernal pools are not pools year-round.  For part of the year they are dry holes or ditches or soggy areas. Vernal pools are places where animals like salamanders live underwater for a short part of their lives.

Marbled Salamander’s jelly-like eggs

Marbled salamanders live close to the vernal pool where they first emerged from their jelly-like eggs. They return to the same vernal pool for breeding. If that vernal pool is cut in half from nearby development, or the drainage of the nearby land is changed and water no longer fills the pond from runoff, or a road has been built that requires them to cross that road to get their very own vernal pond, the the marbled salamanders in that area will die out.

Vernal pools are essential for salamanders including our friends the marbled salamanders. Period.

Vernal pools are important habitats for lots of other animals including invertebrates, other amphibians like frogs and toads, birds, and  mammals. Newly hatched salamander larvae eat plankton – not the plant forms of plankton but the animal forms called zooplankton. They are carnivores for life. As they get bigger, they eat insect eggs and larvae as well as smaller amphibian larvae. In the case of many critters, including marbled salamanders, they might even eat smaller larvae of their own species.²

Animals that eat the critters in vernal pools include herons, geese, ducks, turtles, and snakes. Even animals like deer, raccoons, and mice stop by for a drink of water. The one big advantage of vernal pool life for the critters that lay eggs in them is that fish don’t live there. Animals that eat adult salamanders include snakes, owls, raccoons, skunks, shrews, and weasels. Animals that our adult carnivorous salamander friends eat include earthworms, slugs, snails, centipedes, and all the insects they can find – including mosquitoes!

Marbled Salamander looking out after its eggs

Marbled salamanders are extremely sensitive to the chemicals that can pollute vernal pools. Their eggs and thin skin are porous and offer no protection from what’s dissolved in the water. Chemicals and pollutants that drain into vernal pools stay in the water or sediments. This can be life-threatening to salamander eggs and larvae.

Salamanders that survive these various threats may live as long as four to ten years. They may never see or be seen by people. How do we know they’re even there? Experts in salamanders called  herpetologists³ keep an eye on places where they know marbled salamanders live. During the breeding season they might visit those places because it’s their best chance to see these three to five inch long critters.

Life Cycle

The life cycle of the marbled salamander is unique, different even from its close relative the spotted salamander. Marbled salamanders mate and lay eggs on land in the fall. The female lays between 50 to 100 eggs. The eggs are guarded on land (not in the water) by the female until rain washes the salamander eggs into the nearby vernal pool. Mom salamanders are active parents and that is rare in the amphibian world.

The eggs hatch when they have been underwater for a few days. The underwater larval stage when salamanders have feathery gills behind their heads can be as short as two months and as long as nine months. The juvenile stage lasts for about 15 months while the salamander is adjusting to life on land without gills.4

 

Image combined by Kelly Mack. Some marbled salamander images on this diagram were found at lesillustrations.tumblr.com/post/83739136642/marbled-salamander-ambystoma-opacum-life-cycle

Interesting Facts

  • Cold-blooded, thin skinned salamanders don’t freeze in the winter. They go dormant (not breathing, not eating) when it’s below 40° F. They are able to break down glycogen (a molecule made up of many glucose or sugar molecules) into single glucose atoms and turn their blood into a kind of antifreeze.
  • Three things help marbled salamanders escape from animals that want to eat them.
    • First, they have poison glands on their tails. The poison won’t kill the predator but it tastes so bad that the predator won’t try to eat them again.
    • Second, all salamanders have mucous glands on their skin so their delicate skin won’t dry out. It’s hard to hang onto a slimy salamander. Note: if you’re ever lucky enough to touch a salamander, make sure to get your hands wet so you don’t hurt their skin. And don’t forget to wash your hands afterwards.
    • Third, salamanders can grow back legs and tails if they get bitten off by a predator. It’s a great way to avoid being completely eaten. They have special cells that cover the wound and immediately start making a new leg or tail just like the old one.

Marbled Salamander Super Powers

We already know they’re Super Cool (not freezing when it’s freezing cold) and Super Self-healers (growing back missing tails and legs). But there are more super powers!

  1. Super Hiders! Don’t bother challenging them to a game of hide and seek. You’ll never win.
  2. Super Sally Moms! No other Maryland mole salamander (not the eastern tiger, Jefferson, nor spotted salamanders) looks after the eggs they lay. Sweet!
  3. Super Sentinels! For keeping people on their toes about environmental changes!

A big pat on the head (if we can find one) for our super shy marbled salamanders!

Status

Marbled salamanders are not on Maryland’s List of Rare, Threatened, and Endangered Animals but still need our help!

Bottom Line

Marbled salamanders are beautiful, rare, sensitive to pollution, and highly dependent on natural water cycles. They can serve as excellent ambassadors to Montgomery County residents. Their being here now and in the future is a reason to carefully consider how land can be re-developed or developed for the first time while protecting the land and all of its residents, human and non. Salamanders and protection of vernal pools highlight the need for better management of stormwater.

Salamanders are rapidly disappearing worldwide due to their sensitivity to pollution, habitat loss due to development and urbanization, and climate changes resulting from increased temperatures.

Fungal diseases fueled by the pet trade have severely reduced native salamander populations in Europe and could find their way to the US. Since the US is home to 20 percent of the world’s salamander species, this is a huge concern.5

Currently, marbled salamanders are not endangered in Maryland. The goal right now is building up their numbers to give them a better chance of long-term survival.

How You Can Help

Marbled salamanders are very sensitive to water pollution and human-made threats to sensitive vernal pools that are a crucial part of their life cycles. Climate changes also present serious challenges to salamander survival. Here are some things you can do to help.

  1. Be aware of the amounts of hard surfaces like concrete, and asphalt that are near your home. Please don’t add more. Too many hard surfaces can lead to flash flooding during storms that spill into nearby vernal pools. In vernal pools, the trash and pollutants that are carried along with the runoff stay in the pools. Those materials have nowhere else to go. And neither do salamanders.
  2. Reduce the use of pesticides and fertilizers for the same reason. If those chemicals end up in vernal pools, they stay there and that’s definitely not good for the critters that live there.
  3. Use environmentally friendly soaps when washing your cars at home. Again, what drains away could end up in a vernal pool that marbled salamanders and their cousins might depend on.
  4. See any litter in your neighborhood? Pick it up! Any time it rains, anything left on the ground will end up in our rivers and streams and nearby vernal pools.
  5. Plant native plants and trees – they have deeper roots and allow water to filter into the ground versus running off on hard surfaces.
  6. Are you enjoying our parks? Leave no trace behind!

 

Guest writer:  Gail Melson

Don’t miss out our last blog on Montgomery County’s stream critters, next week, highlighting a very special stream critter: the Yellow Lance  Mussel!

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Citations:

¹Read about hearing and seeing marbled salamanders by a marbled salamander expert here: https://srelherp.uga.edu/projects/dssal.htm.

²Cannibalism happens – from ducklings to rabbits to salamanders and plenty of other animals. It’s a matter of survival sometimes. https://www.businessinsider.com/animals-that-are-cannibals-2018-12

³Herpetologists are experts in other amphibians like frogs and toads as well as reptiles like snakes, turtles, and lizards. It’s a great career option for some people. 

4https://www.chesapeakebay.net/discover/field-guide/entry/marbled_salamander

5https://www.usgs.gov/centers/nwhc/science/batrachochytrium-salamandrivorans-bsal-surveillance?qt-science_center_objects=0#qt-science_center_objects



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