That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information
Everyone associates the poison or “dart” frogs (Family Dendrobatidae) with skin toxins, but it is to the slow, seemingly benign newts and salamanders that we should really pay heed. In many cases their toxins are far more virulent and, unlike those of the poison frogs, they are produced internally and are not dependent upon diet for their existence (in other words, the toxins do not decline after a time in captivity, as is the case for poison frogs!).
One of Earth’s Most Toxic Creatures
Over 200 compounds, some of which are medically significant, have been isolated from newt and salamander skins. Western North America’s rough-skinned newt (Taricha granulosa) possesses what may very well be the salamander world’s most powerful secretions…a single adult packs enough to kill 25,000 mice. More than one person (usually male, drunk and involved in some sort of “initiation” or dare), has suffered fatal consequences after swallowing a rough-skinned newt.
Skin secretions entering tiny cuts have rendered researcher’s limbs numb for hours, and a scientist who rubbed his eyes after touching a “woodland salamander” (I cannot recall the species, but belonging to the red-backed/slimy salamander group) wandered about blind for nearly 3 days before being rescued.
Toxins vs. Eel
Although the California newt’s (Taricha torosa) toxins pale in comparison to those of its rough-skinned cousin, they are not to be trifled with. I kept a California newt with an American eel for 17 years. The eel, a voracious predator that would as soon latch onto my hand as anything else, never once molested its seemingly defenseless tank-mate.
Next time I’ll relate an encounter I generated as a foolish 13 year old working in a pet store, which clearly illustrates the toxicity of even the most familiar of North American newts.
Further Reading
You can read more about the natural history and toxicity of the rough-skinned newt at http://www.amphibiaweb.org/cgi/amphib_query?where-genus=Taricha&where-species=granulosa&account=amphibiaweb
California Newt Image referenced from Wikipedia Commons and originally posted by Justin Johnsen
Great article! I have grown up in Northern California and love our native fauna. A few months ago I collected 4 taricha torosa as larvae. They morphed about 7 weeks ago and so far so good. However they seem very shy and hide under their water dish pretty much all the time. Whenever I lift the dish and release fruit flies or 1/8th inch pinner crickets they eat eagerly. Is this timid behavior normal for taricha torosa? I use coco-fiber substrate with some flukers frog moss over the top. I also created caves using rocks , but they just love going underneath the water dish.
Hello Pedro, Frank Indiviglio here.
Thanks for your interest and the kind words, much appreciated.
They are pretty shy at that size…despite the powerful toxins, a few predators, including certain garter snakes, are immune so it pays for them to be secretive. They often become bolder as they mature.
I’ve also noticed that this species is very bold in the aquatic phase. The amount of time they spend on land varies among different populations – you might try establishing a “shoreline terrarium” with a lager, easily exited water area to see if they might take up an aquatic existence sooner rather than later. They are also easier to care for at that time, as they will take Reptomin and other prepared foods (on land they consume live food only).
They may be choosing the water bowl because it is more secure, or moister, or cooler in temperature. Try modifying other shelters – something small and tight, that provides surface contact, is usually preferred. Cork bark slabs often work well, and can double as rafts when the newts become aquatic. It’s best if they split up a bit… clustering is sometimes associated with a fungal infection (heat may build up, or rubbing against one another may remove protective skin mucus).
Good luck and please keep me posted.
Best regards, Frank Indiviglio.
Thank you for your quick reply Dr. Indiviglio.I was told that after Taricha Torosa morph they take on a more terrestrial existence preferring foothill grasslands and to some degree pinewood or oak forests. Are you saying that I can induce an aquatic phase by changing their terrarium? If so then I would be more than happy to do that as aquatic set ups tend to be easier to observe.
Hello Pedro, Frank Indiviglio here.
Thanks the feedback. They do indeed take up a terrestrial existence, but some populations return to water rather quickly, and spend most of their time in the water. I wouldn’t set them up in an aquatic environment just yet, but perhaps provide a half/land situation, i.e. gravel islands. If they are not from a population that does re-enter water quickly, however, then doing this would not induce them into the aquatic phase any earlier, as far as I know.
Good luck and please keep me posted.
Best regards, Frank Indiviglio.
By the way these specimins were collected at vernal pool in Solano County which is between San Francisco and Sacramento. Would that shed some light as to the water to land ratio requirements?
Hello Pedro, Frank Indiviglio here.
Good thinking…, thanks. If the adults are breeding in a vernal pond then they will likely remain terrestrial until sexual maturity.
If you have a chance and would like to experiment, you might consider providing more water as they mature. We can induce tiger salamander larvae and some other species to transform to the adult stage quickly (and even, in some cases, to change their jaw/tooth structure and diets) by dropping water levels; of course that is an emergency situation but it might be interesting to see what terrestrial phase newts would do if given the opportunity to take to water – perhaps it is a more favorable environment?…just a thought.
Thanks for the interesting thoughts,
Good luck and please keep me posted.
Best regards, Frank Indiviglio.
Dr.Indivigio,
Thank you for your replies. I find it hard to believe that the man that wrote one of my favorite books of all times is actually communicating with me!
This weekend I plan on transforming my terrestrial set up into a semi aquatic set up. I will use plexiglass and silicone to create an aquatic area. I still have the internal cartridge filter that I used when they were larvae. I am thinking maybe 70% land 30% water.
My question is this. Do you think that my T.torosa are too young to do this. They morphed about 8 weeks ago.
Hello Pedro, Frank Indiviglio here.
Thanks so much for your kind words about my book; it means a great deal to me to know that I have produced something that has been of help to others in my field. The second edition of Newts and Salamanders will be out soon. Unfortunately I had to cut out half of the text due to the publisher’s guidelines, but I re-wrote it entirely in an attempt to condense and so save as much as possible. There will be many new photos – most provided by Dick and Patti Bartlett, whose work you may know as well. They have written some of my favorite books, and are in a class all their own.
It’s difficult to predict how your newts will react when given access to water. California newts seem to be somewhat flexible in that regard, so it will be interesting to see what happens. If water is a more favorable habitat in general (which only they will “know”!) then they may very well try it out. Just be sure that they can exit the pool easily.
Good luck and again, thank you very much.
Best regards, Frank Indiviglio.
Dr.Indiviglio,
Pedro here, I hope all is well with you. I changed the setup to semi-aquatic using a foam turtle beach and pieces of leached out oak branches. They seemed a bit overwhelmed by it even after 5 days. So then I went back to terrestrial but I did a substrate change still using coco-fiber and frog moss, but I sort of sunk the water dish into the substrate making it easier for the newts to enter and exit. They seem to really like it! They wander around more and when they do hide away they do so separately. Its funny how a little change can make a huge difference with herps. Thank you so much for your advice!
So I have been feeding the T.torosas H.hydei flies and maggots, and pinner crickets. Recently I started smaller phoenix worms. The larger newts will eat them, but the smaller ones will take a bite but spit them out right away. Are phoenix worms a hit and miss type thing?
Hello Pedro, Frank Indiviglio here.
Thanks for the update, I hope all is well.
I’m glad you tried a few set-ups and have hit upon the right environment. I agree with your observation…small changes are critical, not only in promoting natural behavior but to overall health. By keeping animals in the proper environment, we reduce stress and therefore disease. This is particularly critical with herps, as we know so little about treating them medically.
They may take the worms as they grow, but there are individual preferences as well. If a local store carries them, you might try live blackworms. They are annelids, like earthworms, and a great source of nutrition. Although aquatic, they will live for hours in a small dish sunk into the substrate, where they can be easily found. Most newts love them, and they are of a good size for new metamorphs.
Good luck and please keep me posted.
Best regards, Frank Indiviglio.
Nice post! In addition to the high toxicity, my favorite thing about the various species of is their crazy mating behavior.
Hello Mike, Frank Indiviglio here.
Thanks for your interest in our blog and for the kind words.
Wow!…some video, thank you. I’ve watched mating balls of spotted salamanders, but have never been lucky enough to catch California Newts in the act, although I tried once while on the west coast. Frogs and toads are really something when they get going…but again your video surprised me. Hey are very “single minded” – male American toads will kick at you it you pick up a mated pair, and some have reported them in amplexus with tennis balls!
Good luck, enjoy your field herping and please keep me posted.
Best regards, Frank Indiviglio.
Dr.Indiviglio,
I have another update for you regarding my T.torosa morphs. I planted Philodendron scandens which took off like a bat out of hell. Since then my newts have been even more active and more receptive to foods. The other night I put a big lump of black worms on a piece of wet paper towel. They all started to chow down on it! By morning it was all gone. The skinny ones have fattened up quite a bit already.
Thanks again for all of your help Frank.
Pedro Takahashi (aka) Taka
Hello Pedro, Frank Indiviglio here.
Thanks for the feedback,
Philodendron is great to use with amphibians…exposed roots will also trail into water, nice for aquatic species. I saw some huge philodendron used to great effect with insects and amphibians at the Tama Zoo in Japan…upon my return here I saturated the Bronx Zoo with it, there’s a jungle there now in some exhibits!
Pothos is another useful plant, grows well in water or soil, on gravel. Peace lilies also.
You’ve hit on a very useful general concept concerning cover…shy animals of all kinds often show themselves more, not less, when provided well-planted, complex exhibits. Even nocturnal species are more likely to move about by day under plant cover. You’ll also see more interesting behavior in complex exhibits.
Good luck and please keep me posted.
Best regards, Frank Indiviglio.