Considering species abundance, one doesn’t generally think immediately of North America, but there is one group that is abundant and diverse in the north: the salamanders.
When I was in college ten years ago, I found that many of my classmates were particularly interested in amphibians, and my senior year took a herpetology course myself. It was a good time (not to mention the TA was pretty good looking, but that is another whole story…), and between the labs and extra credit field trips (well, really field trips for no credit except our own personal growth), I got to know this class of animals a little bit. Since then, I have had a seasonal job working with desert tortoises, but nothing with amphibians, and haven’t gone “herp hunting,” as we called it, since I was in college, so I was pleasantly surprised last summer when my daughter and husband came in excitedly telling me they had found a salamander out by the side of the house. As it was our first summer in this home, which is nestled right in the trees with about 3 acres of woods surrounding it, I had wondered and hoped that there would be salamanders here, but hadn’t taken the initiative to check yet. This summer, I can’t claim that I have gone turning over logs and large rocks looking for the cute little guys, but we did find some Red-backed salamanders out by our bird feeders in the spring, and I am proud that we have them on our property and that my daughter is learning to care for them as she does the trilliums and other nature here.
Amphibians, like frogs and caecilians, and classified into the order Caudata, salamanders are represented by approximately 400 species world-wide. Nearly 1/3 of those species are found in the United States and Canada, with the southeastern US being particularly productive, touting 127 different species. North American salamanders exhibit an incredible variety of life strategies for survival, seeming to have evolved to fill every niche possible for their body design. According to Roger Conant and Joseph T. Collins, authors of the Peterson’s Field Guides: Reptiles and Amphibians, Eastern/Central North America edition, “North America boasts an assortment of big, bizarre salamanders that look more like bad dreams than live animals.”
All salamanders have soft, moist skin, which ties them to environments that allow them to retain that moisture, such as forest floors, streams and ponds. Their body shape is elongated, with legs that are squat and out to the side like those of lizards, although not all families have four legs and they can be used for different purposes. Salamanders possess prominent tails in both their larval and adult morphologies. As their main source of food, salamanders consume invertebrates, although one family, Sirenidae, the sirens, are partially herbivorous. They are secretive and nocturnal, taking advantage of the hour when their predators are visually impaired by the darkness, and the relative humidity in the environment is high.
All groups of salamanders that reside in the US and Canada employ egg laying as their reproductive strategy. After a brief courtship, for all but a few families world-wide, internal fertilization is achieved by the male depositing a spermatophore in front of the female, who then retrieves the sperm mass. The sperm is then stored in the female’s body until she is ready to lay her eggs, at which time, each egg is fertilized as it is being laid. Across the different genera of salamanders, the egg mass, number of eggs laid, and size of the eggs differ depending upon the type of environment the animals inhabit. Some salamanders lay their eggs so that their offspring will spend a portion of the life cycle in an aquatic environment. These larva pass through a metamorphosis in which they possess external gills and dorsal fins for swimming, before losing those features to become terrestrial animals with thin tails and no gills. Some salamander families, such as the mudpuppies and waterdogs (Necturus spp.), do not lose their gills and reside exclusively in the water for their entire existence. Some species of the family Plethodontidae, also known as the lungless salamanders, are exclusively terrestrial and young are born fully developed, looking like small adults. Length of time each species spends as a juvenile varies from months to years. One well studied and unique strategy is employed by the red-spotted newt (Notophthalmus viridescens) in which the adult takes on an aquatic morphology, while the juvenile, called a red-eft, lives terrestrially for a number of years, brightly colored and fearless because of the noxious liquid it secretes from it’s skin glands. Metamorphosis from a juvenile into an adult salamander brings us back to the beginning of the cycle with courting, breeding and egg laying.
As you might be beginning to suspect, salamanders are incredibly diverse, and their life histories are both complicated and interesting. While I was researching for this post, I was struck by just how inconsistent the order Caudata is as a whole, and impressed by all the little idiosyncrasies involved in the salamanders’ life strategies. I suppose though that it would not really be that different if one were to study the order Diptera, for example, which consists of flies, mosquitoes, midges, and gnats.
Part of the fun in science is learning just how little you know, so I had originally thought I would humbly highlight a few northeastern North American species so my readers can feel like they know a little about these small vertebrates, but for the sake of space, I think I will turn this project into a series of postings. Keep watch out for: Red-backed salamanders (Plethodon cinereous), Northern Hellbenders (Cryptobranchus alleganiensis), Jefferson salamanders (Ambystoma jeffersonian), and probably more on the Red-spotted Newt (Notophthalmus viridescens).
In the mean time, I encourage you to do some research on your own, or even go “herp hunting.” Start with these tips:
1. Go “herp hunting” during the day: If you have a specific type of salamander you want to find, research at your library or on the internet the habitats that salamander inhabits. If you just want to find some animals, find an area with a large wooded area. Salamanders have a territory size of 1m² (I remembered that from college!), with larger salamanders having slightly larger territories, so the area you search should be large enough to support a population of salamanders. Overturn large rocks and logs. Found one? Cool! Didn’t? Gently replace the log or rock and continue. That’s all. If you want to hold a salamander make sure your hands are clean of harmful chemicals like bug spray and sunscreen (remember these creatures take a lot in through their sensitive skin), and keep your hands moist so they don’t dry out. Replace the salamander to the spot you found it and place the cover gently back down. NEVER take wild animals without a permit, as there may be laws against it, and you don’t want to deplete local and regional populations.
2. Go “herp hunting” during the night: Use a headlamp and search for animals in the same manner as stated above. Salamanders are nocturnal and your search results may be slightly different at night than in the daytime.
3. Get some books out of the library or search the internet for more information on the order Caudata, or do a search for a particular kind of salamander that piques your interest. I suggest starting with field guides such as Peterson’s Field Guides, and moving on from there. James W. Petranka also has an awesome and comprehensive guide: Salamanders of the United States and Canada, which is well researched and discusses all North American species on subjects such as ID, geographic variations, breeding and courtship, reproductive strategies, and aquatic and terrestrial ecologies. Watch out, this one uses big scientific words! (Takes me back to my college days and makes me feel smart…)
4. Start a “herptarium:” Get a pet salamander. Make sure you research your species and have a properly sized tank that has proper physical elements set up for your salamander’s entire life cycle. Also be sure to purchase your salamander from a reputable seller, only purchase captively bred animals, and NEVER take live animals from the wild or buy from someone who has taken animals from the wild.
5. Share salamanders with children by taking one or more out “herp hunting.” Or check out some books with them, such as Salamanders by Emery and Durga Bernhard, an informational book about salamanders’ life history and facts about all the major species. Another popular book, The Salamander Room by Anne Mazer, is about a boy who finds a salamander and then is taken on a daydream fantasy as he answers his mother’s questions about how he will care of it.
I feel like I am learning (or re-learing as it may be) so much, and I hope I have sparked your interest to also continue learning some more about these interesting creatures. I know I am having fun! Let me know if you like this post, if you have any other facts to share, or since we are all human, if you think I got something wrong. Have a great day!