Who is the bigger fool – the fool or the fool that falls for it?
by Stevie Kennedy-Gold
The start of April only means one thing – pranks galore thanks to April Fools Day! Ok, ok, I realize that’s not necessarily true as April also marks that spring has sprung, many small critters are emerging from their hibernations, and we celebrate, among other things, Earth Day and Arbor Day. But we can all agree that April usually starts with a load of laughs, some fibs, and some fools. In the animal kingdom, however, fooling isn’t regulated to one day. In fact, many amphibians and reptiles rely on their ability to fool both predators and prey to survive.
Masters of Disguise
Fig. 1: Because of the large blotches on their backs, people often confuse the nonvenomous gopher snakes with venomous rattlesnakes. Gopher snakes play into this confusion, however, by imitating rattlesnake behaviors.
One of the oldest tricks in the book when it comes to fooling another is to transform to look like someone, or something, else. Although herpetofauna lack access to theatrical wardrobes teeming with makeup and outfits, they evolved behaviors and physical attributes that allow them to imitate other things. The gopher snake (Pituophis catenifer, Fig. 1), for instance, is a totally harmless colubrid species found across the western and middle United States and into Canada. They are beautiful animals, having splotches of gold, reddish-brown, and black along their bodies, and, due to these colorations, are often mistaken for rattlesnakes. What’s more, when spooked, gopher snakes tend to flatten their heads, coil into a strike position, and quickly sway their tails to and fro, a rattlesnake imitation that includes a realistic sound component when it occurs in dry grass. Most snakes are solitary animals and prefer to avoid conflict and avoid expending energy in get-away attempts, so scaring away potential predators through imitation is preferred over fighting and biting. Often times, this imitation works, and potential predators leave the gopher snake alone.
Fig. 2: Smooth horned frog (Proceratophrys boiei) specimens in the collection. Although the points above their eyes have been distorted due to preservation, it is clear to see how these frogs used their coloration, patterning, and morphological features to blend into leaf litter on the forest floor.
Predictably, snakes are not the only masters of disguise. Many frog species have unique morphological features that allow them to resemble other items in nature. The dark brown coloration and the points above the eyes of the smooth horned frog (Proceratophrys boiei) give it the appearance of a leaf (Fig. 2), allowing it to blend seamlessly into the forest floor and enabling it to both evade predators and ambush prey. Similarly, the entirely aquatic Suriname toad (Pipa pipa) looks like a dead leaf in the water due to its brown coloration and flattened body. Unless you’re an omnivore that prefers dead, low-nutrition leaves, the imitation tactics of these frogs improves their chances of survival and fools any prey items not clever enough to see past their disguises.
Not all imitations are meant to help an animal blend in. Sometimes, imitations serve “nefarious” intents. Although not apparent to an outside observer, alligator snapping turtles (Macrochelys temminckii) have a sneaky tactic to lure prey directly into their mouth. The tongues of these turtles evolved a vestigial piece of flesh, called a lingual lure, to protrude from the tip. Alligator snapping turtles will sit on the bottom of lakes and rivers and open their powerful jaws to reveal this pink bit of flesh. They then move the lingual lure around to make it look like a tasty worm, fooling unsuspecting fish right into their giant maws. Spider-tailed horned vipers (Pseudocerastes urarachnoides), a species endemic to Iran, employ a similar tactic, albeit far more noticeably to the casual observer. Admittedly, the common name of this animal gives away the punch line, but, nonetheless, this species of viper evolved to have a unique tail. Much like how a rattlesnakes’ rattle is made of modified scales, the spider-tailed horned viper’s tail scales evolved so that the last few scales bulge out into a small bubble and the scales leading up to that bulge are heavily keeled, or ridged. While keeled scales are common in most species in the Viperidae family, the keeling on these tail scales is extremely exaggerated, making the scales look like long spikes, or even legs. When you combine the long, keeled scales with the large, posterior bulge, the tail of a spider-tailed horned viper actually looks like a spider! With the snakes speckled coloration allowing it to blend into surrounding rocks and a solid tail wiggle performance, the snake’s tail looks like a tasty spider lunch to unsuspecting birds… which then become lunch for the snake. Imitation is the best form of flattery… or maybe a reliable way to fill your belly!
Now You See Me, Now You Don’t
Whereas some reptiles and amphibians are the masters of disguise, allowing them to hide from predators or to lure unsuspecting prey, other herps use subtler bodily alterations to fool potential prey, predators, and even conspecifics (animals of the same species). Take, for example, color changes. Chameleons often come to mind at any mention of lizard color changes, but it is actually a misconception that chameleons perfectly blend into their surroundings, mimicking every leaf and twig in the background. In truth, chameleons and many other lizard species change colors to improve thermoregulation and to communicate with conspecifics – males signaling to females that they’re ready to mate, or relying on darker colors to demonstrate aggression. There are, however, some species of frogs that do lighten or darken their hue to blend into their surroundings. The gray treefrog (Hyla versicolor) is present across most of the eastern and middle United States and, as its name implies, is an arboreal species. Because it spends its time among green leaves and gray-brown tree trunks and branches, the gray treefrog has evolved the ability to change its body coloration so it can blend in perfectly with the substrate upon which it perches. If it is on a bright green leaf, the frog will shift to a green hue. Upon landing on a mossy rock or a lichen-crusted tree trunk, the frog will change to a more gray, blotched hue instead. One second, you can see the animal perfectly and, in the next, it has completely melted away into its surroundings.
Leaving Something Behind
Other herpetofauna use more exuberant tactics to evade capture. Unlike the camouflage-wielding gray treefrog, many lizard and salamander species will self-autotomize their tails to avoid being eaten. In these instances, the herp has already been seen (or, worse, caught by a herpetologist!) and needs a quick getaway. Running away without a distraction means that the predator will likely give chase and possibly capture the lizard or salamander. However, by self-autotomizing – or breaking off – their tails, these animals increase their chances of escaping. This drastic tactic is effective because the tail continues to wriggle around and move once detached from the animals’ body, making it a tasty and easy to grab meal! Many predators become distracted by the tail, leaving the lizard or salamander free to make its escape. Interestingly, this behavior is not strictly regulated to predator attacks. I witnessed a prolonged aggressive battle between two male western fence lizards (Sceloporus occidentalis), where one male lost his tail and, instead of leaving it to writhe on the ground and eventually decompose, the lizard (attempted) to make a hasty, grapple-filled retreat from the other male, all while holding his detached tail in his mouth! Although this seems morbid, it’s actually quite clever – tails require a lot of energy and resources to make, but then the appendage stores energy in the form of meat and fat. This male fence lizard was likely keeping hold of his old tail so that he could later consume it and regain those resources. And, don’t worry, most salamander and lizard species can regrow their autotomized tails (Fig. 3), an ability that many herpetologists take advantage of when we need tissue for genetic studies.
Fig. 3: Example of tail loss and regrowth in a female Anolis carolinensis (green anole). The red arrows points at the old break point, and you can see how the tail color differs in the new growth.
The list of herpetofaunal imitators and imposters, pranksters and fibbers goes on and on. Although these disguises and imitations aren’t meant to make other animals giggle and laugh as our April Fool’s Day pranks often do, these tactics allow these reptiles and animals to live another day, evade unwanted attention, or snag a tasty meal. But, at the end of the day, it really does beg the question… who is the bigger fool – the fool or the fool that falls for it?
Fig. 3: Example of tail loss and regrowth in a female Anolis carolinensis (green anole). The red arrows points at the old break point, and you can see how the tail color differs in the new growth.
Stevie Kennedy-Gold is the collection manager for the Section of Amphibians and Reptiles at Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.
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iirc there are also a few coastal marine fishes with disjunct ranges that stop around cape Mendocino and pick up again around Vancouver Island. I think the kelpfishes Gibbonsia metzi and G. montereyensis might be some? Interesting to hear about the sky salamander having a similar distribution. Not sure if the fish disjunction is real or just a lack of info from the outer coasts of WA and OR tho, but maybe supports the natural dispersal hypothesis for the salamanders?
Oh thank you, this is really good to know. I know practically nothing about the marine ecology in the North Pacific. (Vibrant seas; there is so much sea life in the region, I don’t even know where to begin. I’m more familiar with terrestrial rainforest/PNW landscape,.) Off the top of my head, I know of one marine species, bat stars (Patiria miniata), which have a similarly disjunct distribution. For a long while, I have had some guesses about why some rainforest species have disjunct distribution ranges, separated, isolated in California and Vancouver Island. (Big disclaimer: I am horrible with chemistry/biochemistry. Know little about physics. Bad with technical ecology. Instead, mostly into geography, biogeography, human ecology, historical environmental change, etc. But I love salamanders and PNW geography enough to venture a couple of guesses in this case.) What do you think? I’d love to hear your thoughts.
For anyone interested, we’re talking about Aneides vagrans, a salamander endemic to the Pacific Northwest. Here’s what I said about them: Though, something about the temperate rainforest canopy that might be surprising? The “sky salamander.” Rainforest creature, a lover of fog. [...] Weirdly, there are two separate populations of this salamander, with a great distance between them. Some of these salamanders live in the rainforest of Vancouver Island. But the other population? In the redwoods forest of coastal northern California, the salamanders also permanently reside up to 95 meters above ground in the canopies of redwoods, where moss beds and epiphytic fern mats, resting in bark crevices and on redwoods branches, create refuge and provide small amphibian-friendly microhabitats in the sky. They can spend their entire life up there, in the fog. [...] If this is a coastal rainforest species, why are they living in rainforest of northern California and in the rainforest of Vancouver Island, but not in all that rainforest in between? [...] A leading theory proposed by Canadian ecologists suggests that the salamander made its way to Vancouver Island naturally, in recent centuries/millennia, by rafting on the thousands of large conifer logs that fall into northern California’s water and flow northward towards the Raincoast. (Original post about salamanders living in the canopy.)
Here’s the dilemma. (This is where the salamander lives.)
Aside from the sky salamander, there are a few other terrestrial creatures that I know of, which share a similar disjunct distribution pattern. As for animals, there is Edward’s beach moth (Anarta edwardsii), which is found in coastal California and Vancouver Island, and nowhere in-between despite all of the similar/suitable habitat. (There are some isolated records along Salish Sea coast near Mt. Vernon and Port Angeles in Washington State, to be fair.) There are many species of butterflies, which inhabit coastal dunes and oak-prairie of the Salish Sea lowlands, which are endemic to the PNW. But this Anarta species has one of the coolest disjunct distribution ranges. (Photo and map from Canadian federal government, COSEWIC.)
But the moth might not be a good comparison, because it’s more like a Mediterranean ecosystem species, rather than a rainforest species.
As for plants, Canada’s federal SARA Registry names about 25 that have disjunct populations at Vancouver Island and at milder climates farther south along the PNW/California coast: Graceful beauty ornamental onion; Clarkia purpurea viminea; Ranunculus californicus; Trifolium depauperatum; Montia howellii; Isoetes nuttallii; Woodwardia fimbriata; Vulpia pacifica; Myrica californica; Minuartia pusilla; Microseris bigelovii; and a few others.
When thinking about the disjunct populations of plants/animals living in California and Vancouver Island, I would probably distinguish between two kinds of disjunct ecosystems: (1) Creatures that live in dryland Garry oak savanna/woodland/prairie. And (2) creatures that live in temperate rainforest. I think that the disjunct populations of dryland/oak species make a little more sense, or are more obvious, while the disjunct distribution of rainforest species seem harder to interpret. The Garry oak savanna/woodland of the Salish Sea lowlands at Victoria and the Gulf Islands is in a rain shadow and experiences mild winters, and I would say the ecology is not dissimilar from Mediterranean environments of California; the oak in the Victoria area thus harbors isolated populations of other “Californian” species like endemic prairie-oak butterflies, the sharp-tailed snake (Contia tenuis) and, historically, the Pacific gophersnake (Pituophis catenifer catenifer) on a couple of the Gulf Islands offshore of Victoria. (There is also a disjunct population of Northwestern fence lizards, more typical of Nor-Cal, living on the shores of the Salish Sea.) These make more sense to me, because dry oak-prairie with Mediterranean-climate dry warm summers and mild winters are like distinct pockets of suitable habitat, easier to identify. And the corridor of oak woodland through Medford-Ashland, Willamette Valley, and the South Puget Prairies provides an avenue of dispersal into the Salish Sea lowlands and eastern Vancouver Island’s rain shadow.
But the rainforest species, like the sky salamander?
Even if the salamanders did arrive in Vancouver in the Pleistocene/early Holocene by rafting from California, there are some qualities of Vancouver Island that I think might’ve been welcoming to the salamanders.
1. Glacial refugia: The Brookes Peninsula (northwestern Vancouver Island) seems to have operated as a glacial refugia for terrestrial species, notably some ferns, mosses, and lichens. Canada’s SARA Registry, for material on the Brookes refugia, recommends: Shafer et al. 2010; Hebda and Haggarty 1997; Pojar 1984. (Rainforest species that used to live all across the PNW between the island and northern California may have lost their populations in Washington/Oregon, but survived on the island and in California.)
2. Mild winters and/or less snow. Northern California and the western shore of Vancouver Island may provide milder winters compared to rainforest of Cascades slopes in Washington/Oregon. I know this might sound silly, given that the western shores of Vancouver Island get completely battered by severe violent oceanic storms and are at higher latitudes than Washington/Oregon, but the western shores of Vancouver Island (being so “hyper-maritime” compared to Washington/Oregon, even more marine-influenced) receive more rain in winter, compared to winter snow in Washington/Oregon. For salamanders and mosses/lichens/ferns that can survive cold/violent wind but don’t like snow, this might be suitable for extending activity seasons.
3. Consistent year-round moisture (lots of fog in Nor-Cal which redwoods epiphyte communities access to maintain moist microclimates, and lots of liquid/rain on Vancouver Island relative to the more-seasonal precipitation of Washington/Oregon). Just guessing, but if the rainforest of Washington/Oregon is just a bit seasonal, receiving rain/moisture at specific times/seasons during the year, then the western shores of Vancouver Island and the redwoods forests of coastal northern California might receive more consistent wetness/moisture? This is probably more obvious at western Vancovuer Island, one of the wettest/rainiest places on the planet. And again, I know it might sound silly, but the redwoods in California? I know that rain is seasonal in Nor-Cal, and I know that temperatures and evapotranspiration are higher here, but the fog, the consistent fog even in summer, might partially compensate, by providing a source of moisture for salamanders and plants that would prefer to live in a wet hyper-maritime rainforest but can also manage to survive by taking advantage of fog.
Here, in the Canadian federal government’s biogeoclimatic region classifications, the western shore of Vancouver Island would pretty much be the most significant site that is simultaneously “very wet” and “hypermaritime.” Very wet = good moisture for salamanders, ferns, and moss. Hypermaritime = insulated against snowy frigid winters. (Labeled here as “VH1.”) The Great Bear Rainforest along the mainland would also be “very wet / hypermaritime” but is more mountainous and at higher latitudes, not exactly nice for the salamanders.
Also: canopy microclimates. As with the sky salamander, the researchers focused on these amphibians discuss how the epiphytic fern mats in redwoods (and Douglas fir) canopies collect so much moisture, and are at such high altitude relative to the forest floor, that the fern mats produce their own microclimates. Even in summer, when there is less rain, the amount of marine fog that rolls through the redwoods forest provides a source of moisture for the epiphyte communites to extract.
I also want to mention some “typical” sub-regions and classifications of the PNW rainforest, to say that I kinda think that Vancouver Island’s rainforest doesn’t get enough credit in US/EPA ecoregion classifications. I think it might make more sense to distinguish Vancouver Island’s rainforest from the rainforest of Washington/Oregon, with which it usually gets categorized as a contiguous ecoregion. I know that, typically, some ecologists/geographers would distinguish 4 sub-regions of the PNW rainforest. It seems like these distinctions were influenced by a late-1990s publication from Ecotrust (”Rainforests of Home,” mostly about salmon and watershed health).
Usually, Vancouver Island rainforest just gets lumped together with Washington/Oregon rainforest as “seasonal / mild.” So maybe it’s possible that both the California redwoods zone and western Vancouver Island are distinct from Washington/Oregon rainforest, and are similarly more-favorable for the sky salamander.
My understanding is that Vancouver Island’s rainforest is much wetter than Washington/Oregon.
I think that maps of differing rainforest soils better represent the distinction between Vancouver Island and Washington/Oregon:
I don’t know, maybe this too:
Between the good wintertime plant hardiness of that redwoods zone and western Vancouver Island, the rainforest of Washington/Oregon might be less hospitable in winter, depending on the metrics you used to judge plant hardiness. Like, I’m not saying that western Vancouver Island’s winter season is necessarily more hospitable to plants than the Washington/Oregon rainforest farther south, but is it possible that the ferns/mosses/lichens that already live on western Vancouver Island are hardy to begin with, and also do well because of winter rain, as opposed to winter snow of the Cascades? I don’t know.
As for marine creatures, the two that I was aware of were these:
-- Eisnea arborea, a seawood, disjunct distribution at Haida/Vancouver and central California.
-- a sea star, disjunct distribution Tlingit/”Alexander” Islands, Haida, Vancouver, and central California.
“No Bat Star Zone.” Lol.
This map from ChrisM’s “The Echinoblog.” [Good discussion of bat stars if anyone’s interested.]
Like I mentioned, there are a few other vertebrates that have a disjunct distribution, but they’re more like prairie-oak, dryland, or Mediterranean species.
Like this. (Northwestern fence lizard and sharp-tailed snake.)
(Sorry for the shitty maps. Again, I am forced to use M!crosoft Paint, the “working-class Arc-GIS.”)
But again, I know nothing of marine biology, really. And I imagine there are so many more influences on underwater ecology here, more obscure than what happens on land.
Love these creatures, regardless.
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