For our first herpetology field excursion of the semester we went to Caw Caw Interpretive Center and Park. With thigh boots strapped on and nets/shovels in hand, we set out to see what wide range of herp fauna we could uncover. In our eagerness to find the greatest number & variety of diverse specimens, we left no stone (or in this case log) unturned as we traveled far away from the rest of the pack into the swamps. At first we were looking for snakes but after turning over a log on a patch of dry land we saw something move and the chase began. While Shaun was knee deep in the water still in search of a water snake, Hudson and I began our frenzied leaf digging to find whatever we had seen moving beneath the log seconds ago. He said he saw something go left and I saw something go right so we each chased our prospective finds, his chase to no avail but mine ending in a tail.
We decided later that he was chasing the body of the salamander whose tail I uncovered. The clever beast had done what is known as tail autotomy and it worked just as it is designed to. When a salamander feels threatened (typically by the presence of a looming predator) it can release its tail distracting the predator and allowing a swift escape. Tail autotomy occurs with limited damage to the creature's well being because of several well placed features in its anatomy. Species which tail autotomize separate at "fracture planes" which are preexisting areas of weakness allowing easy separation. There is voluntary muscle contraction that occurs facilitating skin and muscle to let go of the tail as well as an arterial sphincter system to prevent major blood loss. Once the tail is detached it can continue to wiggle around for quite some time on its own with the aid of anaerobic respiration. This provides enough of a distraction for the salamander or lizard to sneak away unnoticed.
Just like the amateurs we are, we fell for the salamander's ruse and chased the tail, proving the effectiveness of this adaptation.
Unfortunately, due to my shoddy film making I haven't been able to identify the species. Any ideas classmates?
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6 comments:
Cool post! I always thought of tail autonomy as a way to narrowly escape the jaws of a predator. For instance, a lizard being captured by his tail can then detach his tail to avoid being eaten. I've never actually thought of it in this perspective in which a lizard detaches his tail in order to confuse a predator (you guys) during a hunt.
Gee wiz Shan! Sounds like we had quite the adventure! Thank you for putting me in the story. I went home and looked at my notes and looked for which family of salamander are known to have tail autonomy. The family that I think is most consistent with the tail we found and the location we were in would be the local species Hemidactylium scutatum which is the only local species of the family Hemidactyliinae! They are known for having tail autonomy, are found in locations much like Caw Caw where we were, and they are a salamander after all!
Hey Shan! Did you know that Hemidactyliinae have a biphaisc life-cycle that begins as an egg in water and where aquatic larva are born and then they metamorphose (unless they retain their paedomorphic traits like internal gills and finned tails) and became capable of a filling the niche of a terrestrial life. They have 4 toes on their hind legs which is what gave them their common name the four-toed salamander, but if you ask me they should be called the tail-losing salamander. The appearance is generally a white belly with black stripes!
Great video! The tail didn't seem to have any scales, so it was probably a salamander. But if it was in a dry habitat, I wonder whether it could've been a lizard. Was there water nearby? How dry was it?
I like Hudson's guess about the species. But lots of salamanders can autotomize their tails. Check a range map to see if H. scutatum is a viable option. What salamander might have a tail that is medium brown on top with darker brown sides?
Good point Dr. Welch, I decided it was a salamander rather than a lizard because we were on a small patch of land (or just a high point of branches and leaves) surrounded by swampy water. This type of moist environment is favored by salamanders.
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