My 2017 Amphibian Review

This past week, temperatures in Ohio soared into the mid-60's, and rain soaked the ground. Although it was still a bit early, some of the salamanders and frogs across the southern half of the state decided they would attempt the journey from their overwintering territories to their vernal pools in hopes of breeding. Their attempts were premature—the weather soon dipped below freezing, and a snowstorm moved across the state—but it got me excited for springtime. To get me through the remaining days of winter, I've decided to put together two posts reflecting on some of the species of amphibians and reptiles I saw last year. I'll start with the amphibians, as they are the first of the "herps" to become active during the year.

Every year, people from around the eastern US look forward to the annual salamander migration. Throughout the forests of the east in the early spring, several species of salamanders belonging to the family Ambystomatidae venture forth from their subterranean homes and migrate upwards of a mile overland to reach vernal pools and ponds to breed in. This event is triggered by the weather, and it typically occurs the first night in spring in which the soil is not frozen, the air temperature remains above 50 °F, and it is either raining or it had rained all day and the ground is still wet. In southeast Ohio, "the night" happens most often between mid-March and the beginning of April. But 2017 was an abnormal year; we experienced extremely wet and warm nights toward the end of January and throughout February. This triggered some, but not all, of the salamanders to migrate early, such as this Spotted Salamander (Ambystoma maculatum) which migrated to a vernal pool on the night of February 7th, 2017—over a whole month earlier than what it normally would.

The Spotted Salamanders weren't the only migratory species to be out the night of Feb. 7, 2017. This Jefferson Salamander (Ambystoma jeffersonianum) was also making his way to a vernal pool. Migrating early, especially if a cold snap occurs right after, can be quite harmful for such migratory salamander species. Right after that night, people posted photos of vernal pools full of dead Jefferson Salamanders late last winter—they had frozen to death. Such instances will most likely increase in the future, as Ohio will face an increase in abnormal weather patterns due to climate change. Ohio is predicted to experience higher winter and spring rainfalls and warmer winter and spring temperatures over the next 100 years, and this will undoubtedly affect migratory salamanders.

Just how it will impact the salamanders is uncertain, but the end effect will more than likely be detrimental. Warmer temperatures and rainfall events earlier in the year will most likely trigger Ambystomatid salamanders to migrate earlier and breed earlier. In addition to the possibility of freezing to death due to the ever present threat of cold snaps in late winter, we could also possibly end up seeing an "out-of-sync cycles" effect, in which the salamander larvae are in the vernal pools, but their food might not be there. We are already seeing this occur with various species of birds. Migration in birds is relatively fixed and triggered by the amount of daylight. Their migration is supposed to be synchronized prior to the peak of mass insect activity so the nestlings will have abundant food available, but insect activity is happening earlier and earlier due to climate change. This is resulting in birds migrating to an area without that much food, and nesting success is decreasing because of it. Could we see such a problem arising with migratory salamanders? Although it’s too early to tell, it’s something herpetologists will be keeping tabs on over the years.

Not all salamanders migrate; in fact, the vast majority of species don't. For example, of the 24 species of salamanders which can be found in Ohio, only 7 migrate. The others are either fully/mostly terrestrial or fully aquatic, and they breed where they live. One of the more common terrestrial and non-migratory salamanders in the state is the Northern Slimy Salamander (Plethodon glutinosus glutinosus). This species can be found throughout the southern and eastern halves of Ohio. Their name stems from their defensive behavior; if a predator (or a curious human) messes with a Slimy Salamander, the salamander will excrete this incredibly sticky and glue-like secretion from its skin. It will then try to rub this secretion all over the potential threat, which will hopefully deter whatever that threat is.

One of my absolute favorite salamanders to see is the Red Salamander (Pseudotriton ruber). This species is a large one, with adult individuals coming in at 5-7 inches in length! The Red Salamander can be found throughout the eastern half of Ohio, where it spends its time either hiding under rocks and logs alongside forested brooks and springs, or within the water itself.

You might be wondering why it would benefit a salamander to be so vividly colored. Wouldn't a large red and black salamander scream "EAT ME" to predators? Well, it's actually the opposite! Bright coloration can be a sign of toxicity. Such conspicuous coloration/patterning is called aposematic coloration, which is more commonly known as a warning coloration. The Red Salamander, for example, has a toxin located throughout its skin which makes it poisonous to potential predators. As a result, the species evolved aposematic coloration to warn predators that messing with them is probably a bad idea. But there's something more complex going on than just simple aposematism. Several salamanders in the eastern US have evolved a similar red/orange coloration with black dots, and it seems to be a case of mimicry. Take, for example, Red Salamanders, Mud Salamanders, and the Red Eft stage of the Eastern Newt. All three of these species are toxic, and they have all converged on a similar red/orange coloration with black dots. This is a case of Mullerian mimicry, in which two or more toxic species converged on a similar appearance. The evolutionary idea behind Mullerian mimicry is that predators will only have to learn to associate one type of coloration with danger, despite there being 2+ toxic species in question. Mullerian mimicry benefits both the toxic species—which are more likely to be recognized as dangerous—and the predators—which are more likely to recognize the danger.

One last salamander! Meet the Long-Tailed Salamander (Eurycea longicauda). For years, this species had evaded me; and then 2017 happened. Not only did I see my lifer early in the summer, but I ended up seeing several more throughout the year, including 3 on one day! As the name implies, the Long-Tailed Salamander has an extremely long tail relative to its body; in fact, the tail typically accounts for around 60% of its total body length. They're a strikingly beautiful species, but it can take some searching to see one. The Long-Tailed Salamander can be found throughout southern and eastern Ohio, where they typically inhabit limestone or shale-based streams, caves, and springs. While the adults are terrestrial, the larvae are fully aquatic, and so the adults typically live close to appropriate aquatic habitats. In such appropriate locales—typically alongside streams or nearby seeps and springs—they spend their day foraging underneath rocks and logs. The individual pictured above was found in Adams County, where it was living under a limestone rock by a stream with a limestone bed.

It wouldn't be a post on amphibians without mentioning frogs, so I'll end on with the most exciting amphibian species that I saw in 2017. This is the Eastern Spadefoot (Scaphiopus holbrookii). The Eastern Spadefoot is a notoriously hard species to see in Ohio for two reasons: their rarity and their life history. Regarding its rarity, the Eastern Spadefoot is listed as Endangered in the state of Ohio. Although it's hard to find exact information on their current range in Ohio—different organizations don't seem to agree on which counties have and don’t have populations, and just how many of those populations are extinct and extant—it can be safely said that this species has only ever been found in a handful of counties. Of those recorded populations, many have died out over the past century due to a variety of reasons, both known and unknown. ODNR reports that only 5 distinct populations of the Eastern Spadefoot remain in Ohio, and no one really knows how how many individuals are in each of these populations.

Regarding its life history, the Eastern Spadefoot has a lifestyle that makes it rather difficult to go look for, even if you know exactly where a population is. The Eastern Spadefoot is an explosive breeder that's more akin to frogs inhabiting the desert southwest. For nearly the entirety of the year, this frog stays underground, where it lives in burrows in sandy areas adjacent to a few rivers in southeastern Ohio. When they're underground, they're essentially impossible to detect. They only emerge to breed, and breeding is triggered by very specific weather conditions. If there is a torrential rain event of 2+ inches of rain within a 24-hour period between the months of March and September, dozens and dozens of individuals might venture forth from their subterranean homes come nightfall to breed in the ephemeral pools the heavy rainfall created. The individuals pictured in this post were found on a visit to a known location in Athens County (all locations are kept secret to prevent unnecessary strain on the population) after nearly 2.3 inches of rain fell over the course of one and a half days.

Eastern Spadefoots are strange. They look strange, they sound strange, and they have a strange life history for a frog species that lives in the eastern US. The unusual name of "spadefoot" comes from a darkly-colored, hardened spur on their back legs that they use like a spade to help them dig into loose, sandy soil. With use of this specialized "tool," a Spadefoot can easily—and quickly—burrow into the soil, like the individual above. I couldn't get a photo of the spade (because the Eastern Spadefoot is endangered, it is illegal to touch the animal), but here is a link that will show you what I'm talking about: Spadefoot spade.

In a few days (or a couple weeks) I'll be posting the second installment covering some of my favorite reptiles from 2017, so keep your eye out for that post! Thanks for reading!

An Ode to the Common Gartersnake

I love snakes, and my favorite species is the Common Gartersnake, Thamnophis sirtalis. As the name implies, this species happens to be one of the most common snakes in much of the United States. But although the Common Gartersnake is abundant and widespread, many people don't give these snakes much thought; our thoughts are preoccupied on "cooler" snake species, like Timber Rattlesnakes, or Rough Green Snakes, or Indigo Snakes. We like the flashier and the rarer species, and we oftentimes pay little attention to the common species that we see all the time. However, the Common Gartersnake is an awesome species as well, and in this post I want to shed some light on this commonly-seen, yet commonly-dismissed, snake.

Before we jump in to ecology and the like, let's talk about names. The scientific name of this species is Thamnophis sirtalis. That's easy enough; this name was officially agreed upon by herpetologists. But then we have the common name, and you’ll find several of those. I was originally taught these snakes were "garden snakes," which is a name many people call them by. You might have heard someone call them “gardener snakes” as well. 

The real common name, however, is "Gartersnake." The people who originally gave this name to this snake did so due to its patterning, which resembled the stripes on the garters commonly worn by people back then. Since people don't really wear garters nowadays, that resemblance became lost on the general public. For many people, the name morphed into "garden snake" or the like, as this sounded similar to garter, and people would sometimes find these snakes in their garden. The altered name made sense for many people. However, in keeping with the naming tradition, the real common name continues to be the Gartersnake. There are several other species of Gartersnake in the Thamnophis genus, but T. sirtalis is the most common and widespread of those species, and is consequently called the Common Gartersnake. There are also several subspecies of the Common Gartersnake, and the one in Ohio is the Eastern Common Gartersnake, Thamnophis sirtalis sirtalis. When talking about this specific subspecies, most people drop the "Common" from the name and simply call it the Eastern Gartersnake.

There are a couple more things to mention about the Common Gartersnake before jumping into its natural history. First, the Common Gartersnake is a completely harmless, non-venomous snake. Second, there's a myth that the Common Gartersnake will not bite people. That's not necessarily true. If you pick up a Common Gartersnake, there's a good chance it might bite you (especially if it's a female). The good news, however, is that their bite is nothing to worry about. In fact, it doesn't really hurt at all. What's the best way to avoid the bite of any snake? It's simple: keep your distance and leave the snake alone. Snakes don't like confrontation, and they won't do anything to you unless you do something to them first.

As I mentioned earlier, Common Gartersnakes are really widespread and abundant. This is primarily due to their flexible habitat preferences. Instead of requiring a specific type of habitat, these snakes can easily adapt to a variety of habitats. They inhabit forests, old fields, marshes, city parks, suburbs, and an assortment of other places. Oftentimes they prefer being near some source of water, like the individual pictured above who was only a few yards from a stream.

Just to give you an idea of where Common Gartersnakes can thrive, nearly all the individuals pictured in this post were found in this sliver of rather low-quality urban habitat. This scene is from Ohio University, near the Baker Student Center. OU's campus has several small areas like this one, with young trees and heavy groundcover. These small areas provide adequate habitat for a population of Common Gartersnakes. The specific strip pictured above contains their hibernaculum, which is a protected location in which some animals spend their winter. For ectothermic (or "cold-blooded") snakes, winter is too cold to be active; as a result, they find a protected cove somewhere within the ground (or in this case a man-made retaining wall) to overwinter in. These snake hibernacula nearly always contain several individuals (this one contains at least 15), but some hibernacula can contain hundreds, if not thousands, of individuals all spending the winter together.

As a quick aside, do you know how awesome it is for a reptile lover to have a snake hibernaculum on their campus? It's amazing.

When winter wanes, and the warmth of spring begins, the Common Gartersnakes will emerge from their hibernaculum. In Ohio, this typically takes place in late March or early April. Well, normally at least. So far, 2017 has been weird when it comes to the weather. The mild winter, coupled with many recent days being in the 60's and 70's, has made many snakes exit their hibernacula really early. In 2016, the Gartersnakes exited the Ohio University hibernaculum in mid-March. This year, the snakes emerged from the hibernaculum in mid-February, a whole month earlier. This is a pattern playing out across southern Ohio this year for a variety of organisms. Many plants are flowering or budding about 20 days earlier than they normally do, amphibians migrated about 20-30 days earlier than they typically do, and even some birds are migrating through Ohio a week or two earlier than normal. Hopefully this doesn't negatively affect the early-rising Gartersnakes, who have since been subjected to about a week with freezing temperatures, but only time will tell.

When Common Gartersnakes emerge from their hibernaculum, one thing is on their mind: it's time to mate. Males will emerge first, waiting around the hibernaculum exit for the females. Once the females emerge, the males will begin vying for the chance to mate with a given female. You end up with scenes like the one above, often described as a "mating ball." In this instance, two males are both trying to mate with the single larger female. Interestingly, both males might end up being successful. A female has several eggs available, and each egg can end up being fertilized by a different male. This results in mixed paternity, where a single clutch of a female's offspring might be the result of several males. This is really common in Gartersnakes, with up to 70% of all clutches exhibiting mixed paternity.

Even more interesting is the fact that the Common Gartersnake gives live birth. Most, but not all, snakes lay eggs, which then hatch out on their own. The female Common Gartersnake, on the other hand, never lays her eggs. The eggs get fertilized by the males, but then stay within the female. These eggs then develop and eventually hatch within the female, who then gives birth to juvenile snakes instead of the eggs like most other snake species. Although this appears similar to how mammals give birth, it is quite different. With mammals, the female actively exchanges oxygen, food, and other substances with the growing fetus. With live-young-bearing snakes, however, the female never exchanges anything with the fetuses. Instead, the eggs in which the fetuses are contained in have all the substances required for development; the female simply carries these eggs inside of her instead of depositing somewhere in a nest or the like.

Like other reptiles, Common Gartersnakes are ectothermic (AKA "cold-blooded," but that isn't really a good term as their blood isn't always "cold," and it can actually be warmer than the temperature of our blood). Ectothermy is where an organism doesn't produce its own body heat through metabolic processes, but instead relies on environmental heat. We humans are, on the other hand, endothermic, meaning we create our own body heat through metabolic processes. When an organism is ectothermic, they are at the mercy of the environment. If it's too cold outside, an ectothermic animal cannot function and may die. If it's too hot, that ectothermic animal also can't function and may die. As a result, ectothermic animals must thermoregulate, meaning they must regulate their body temperature by either moving to a warmer location or moving to a cooler location, depending on their current need. Common Gartersnakes do this by basking in the sun when they want to heat up, or retreating to a shaded area when they want to cool down.

Because of the thermal constraints placed on Common Gartersnakes, one could imagine that any sort of characteristic which makes them stay warmer would be advantageous. A common example of this melanism. Melanism is a condition in which an animal has an abnormally high level of melanin in their skin. Melanin is a dark pigment within the skin of most organisms that gives rise to dark coloration. The dark stripes running down the body of most Common Gartersnakes are a result of melanin. Sometimes there will be a mutation in the melanin-regulating genes of a Gartersnake's DNA, and those genes will create way more melanin than they should. The result? A completely black Common Gartersnake, just like the one pictured above.

Melanism is a normally occurring, albeit rare, condition (like albinism) within most animals, but we don't see many melanistic animals because being melanistic normally isn't an advantage. However, being melanistic is a big plus for Common Gartersnakes. The color black absorbs all the wavelengths of the white light of the Sun, so a melanistic individual can absorb more heat energy than a normal-colored individual. In fact, one study found that melanistic individuals were able to stay about 2°F warmer than their normal counterparts. In the northern portions of the Gartersnake's range, where the temperatures are much cooler, this ability to remain relatively warmer gives melanistic individuals an advantage; they can be active earlier and for longer periods of time, meaning they can hunt more and end up growing bigger. These melanistic individuals end up doing better than the normal individuals, and the melanism-causing genes end up being passed on to more and more baby snakes. This selective advantage has resulted in up to 50% of the Common Gartersnakes around the Western Basin of Lake Erie being melanistic. The individual pictured in the last two photos, for example, was from this region.

Peek-a-boo.

Speaking of feeding, what do Common Gartersnakes eat? It turns out they feed on a variety of organisms. Common Gartersnakes primarily feed on worms, insects, small crustaceans like crayfish, and amphibians. Larger individuals will occasionally hunt down baby birds, lizards, other snakes, and small mammals such as mice. However, Common Gartersnakes must also watch their back, as they are sometimes eaten by larger animals such as other snakes, birds, and small to mid-sized mammals (such as raccoons and even shrews!).

The Common Gartersnake is probably the most abundant snake species we have in Ohio. This species lives in every single county here, and you can probably find one if you keep a sharp eye out while hiking through appropriate habitat. They're beautiful snakes in my opinion, and I can't help but get excited every time I see one. Next time you see a Common Gartersnake, take a closer look!

Thanks for reading!