Here are some lovely frogs I photographed at the Universidad de los Andes in Bogotá. Click photos to enlarge (you can do this twice in succession).
Hemiphractus fasciatus (you can see the same frog’s remarkable gape here):
Phyllomedusa venusta. This frog becomes more camouflaged in the second picture, when it’s sitting amidst leaves:
Some of the gorgeous jeweled “harlequin frogs”. Phyllobates bicolor:
Phyllobates aurotaenia:
Phyllobates terribilis, the famous “golden poison frog”:
This frog is the world’s most poisonous vertebrate. It has in its skin lethal quantities of alkaloid toxins (obtained from its diet) that are used purely as defense against predators. Indigenous peoples make poison darts by heating the frogs in a fire and dipping points into the exudate.
Amphiweb notes:
The combination of batrachotoxin and homobatrachotoxin is produced in quantities up to 1900 micrograms per frog, which is at least 20-fold more than other toxic species in the family Dendrobatidae. The range of batrachotoxin-homobatrachotoxin produced by individual frogs was 700-1900 micrograms, with an average of 1100 micrograms per frog. The lethal dose of batrachotoxin-homobatrachotoxin for a 20 gram white laboratory mouse is .05 micrograms when injected subcutaneously. Thus one P. terribilis frog skin contains enough toxin to kill about 22,000 mice. The lethal dose of batrachotoxin for humans is not known but has been estimated at 200 micrograms, with a single frog thus potentially holding enough poison to kill about 10 humans.
Note that this frog is small, too: about 45 mm (ca. 1 and 3/4 inches) long.
Oophaga histrionica:
Atelopus, apparently undescribed species:
Another shot of P. terribilis, showing its inky nose and feet:
These frogs were photographed in the lab of Vicky Flechas at UdlA, who, with her husband Andrew Crawford, hosted me. Many thanks for the hospitality and photography! Here’s Vicky in her meticulously ordered frog lab:
For a second there, I thought you photographed all these in the wild. Really beautiful and interesting creatures.
They are gorgeous! The Hemifractus with its mouth open looks like it has swallowed an egg yolk – is the yellow its tongue? I wonder why it is pigmented yellow – or am I being selectionist?!
Colombia is a bit south of my expertise, but here are some suggested ID’s (in order of the photos):
1)Hemiphractus fasciatus (Jerry’s ID)
2)A hylid I haven’t tried to figure out.
3)The same hylid.
3)Phyllobates terribilis, the world’s most poisonous frog.
4)Phyllobates aurotaenia.
5)Phyllobates terribilis.
6)A dendrobatid (poison dart frog).
6)Atelopus sp. (a toad, not a poison dart frog).
7)Phyllobates terribilis.
Phyllobates is a genus in the poison dart frog family. P. terribilis is actually dangerous to touch. Coincindentally, I saw a couple of live ones at the Milwaukee Public Museum yesterday. I was fortunate to visit Chuck Myers and see his colony at the American Museum of Natural History shortly after he and colleagues described the species. The species description’s first section is entitled “Introduction and warning”, surely a unique heading in the annals of systematic zoology! For a recent systematic treatment of all the poison dart frogs, see T. Grant et al. (2006) in the Bulletin of the American Museum.
UPDATE. I see Jerry has labeled 3 as P. bicolor. This is not unreasonable, but bicolor‘s limbs are generally darker, and of at least a different hue than the dorsal coloration. These two look all yellow, but then the dorsal side of their limbs (especially the hind ones) can’t be seen well in this picture. The common name “harlequin frogs” is usually applied to toads of the genus Atelopus, not to poison dart frogs.
UPDATE II. Jerry’s updated ID’s and other info in the main post. I’d just add that P. terribilis is so toxic, that the Embera Choco Indians, who use them for dart poison, need only wipe the tip of their darts across a living frog’s back to gain a fatal dose of toxins! The species description by Chuck Myers, John Daly and Borys Malkin contains a large section on the ethnography of dart hunting.
What I was going to say. And that there are also green & orange morphs of P. terribilis. And that it loses toxicity in captivity, and is widely kept in the frog hobby.
Nice pictures!
I heart frogs – and these ones are particularly beautiful:)
Mmmmm…frog licking P. terribilis. Takes you places you can’t come back…but it’s not for the living, dude.
Ribbit Ribbit!!! Thank you Dr. Coyne! 🙂
In Tulsa, Oklahoma (of all places), the zoo has an extensive exhibit of these little beauties.
They’re in one of the indoor “natural habitat” exhibits, but there are no glass walls, or even wire mesh barriers separating the frogs from visitor. Merely a low concrete wall (upon which apparently the frogs do not climb).
You have to be patient and search quietly for a little bit, but you’ll find several species there.
By far the best part of the Tulsa Zoo, with the possible exception of the statue of Ganesh next to the elephant exhibit. There was a kerfuffle about that by the you-know-whats.
Figured that the toxin, since dietary outsourced, is not a peptide (vs. eg snake and cone snail venoms), and it isn’t. But from Wikipedia this further tidbit:
…in 1990 it was discovered that the skin and feathers of some bird species in New Guinea, such as the Hooded Pitohui, contain the toxin on their skin and feathers. Like the dart frogs, it is believed they ingest the toxin from a food source and then secrete it. Specifically, the toxin has been recently discovered in melyrid beetles from New Guinea (the genus Choresine),[3] making them the likely source of the toxin in the birds that consume them.
[3]: Dumbacher JP, Wako A, Derrickson SR, Samuelson A, Spande TF, Daly JW (November 2004). “Melyrid beetles (Choresine): a putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds”. Proc. Natl. Acad. Sci. U.S.A. 101 (45): 15857–60. doi:10.1073/pnas.0407197101. PMID 15520388. PMC 528779. http://www.pnas.org/cgi/pmidlookup?view=long&pmid=15520388.
Couldn’t the frog’s toxicity be considered a possible spandrel? If the frog took to consuming plants high in alkaloids as a way of avoiding competition, its toxicity (and selective benefits from it) could be a byproduct of that.
Could someone explain to me the evolutionary advantage of being poisonous? I would assume that this is an adaptation… But I fail to understand how being poisonous has survival/selfish gene benefit.
Only things I can come up with is, if the poison is *extremely* fast acting, such that it would literally save an animal in mid-bite. I find this unlikely… The other option I can think of is kinship (as in, a poisonous parent saves his kids from being eaten), but this also requires the poison to be very quick, and it requires the animal to have relative proximity to kin. As far as I know, this isn’t the case with frogs? So it also seems highly unlikely to me…
Would appreciate any clarification on this! Thanks!
Poisons may also taste bad.
Predators in Florida that try to eat the Bufo marinus poisonous toad there (invasive) often vomit it up still alive.
The alkaloids are extremely bitter, I’m told, and can be perceived immediately on mouthing the prey. Thus, your scenario about being saved in mid-bite is a likely one here. As you note, if an attack on the frog were always lethal, then there would be no advantage to the frog’s being poisonous, even if it killed its predator posthumously.
But, what’s the phenotype of death? Just rapidly keeling over, or some prolonged violent retching etc first? If the latter, a co-predator might observe and conclude that these are to be avoided, anti-mirror neurons kick in, etc.
Also, what does the toxin target – a neurotransmitter circuit? And what kinds of predators is it active on – presumably all mammals, but reptiles (eg snakes) too? Birds?
Frog pics are lovely, but what is the research the lab of Vicky Flechas is involved with?
‘Flechas’ means ‘arrows’, so it’s appropriate she’s studying poison arrow frogs.
If there is a high prey : predator ratio, I could easily see a species-level evolutionary advantage to killing off predators, even if an individual frog were killed in the process.
If poison is an energy costly thing to make (I would guess it is), such a system would never work, because any individual which didn’t bother making poison would be better off than those which did, and you’d end up with noone making poison, regardless of it being better for the species in the long run…
Thanks for all the answers! I guess my first suggestion is likely then, it does make more sense to me now, as a predator would know to avoid poisonous things anyway, and a prey could ride on this by creating its own…
In this (most unusual) case, he prey apparently gets the toxin, which it presumably is unable to metabolize, from the beetles it eats, so it comes at no metabolic effort. See 8. above, and http://en.wikipedia.org/wiki/Batrachotoxin
Doesn’t the bright color of such frogs function as a warning of toxicity? Predators would know to leave them alone. Or is color more for camouflage or for attracting a mate? As much as we can tell these things. I imagine a study where non-toxic frogs are disguised as toxic ones to see if predators leave them alone.
daveau:
scroll down to post 12 and check the link I put there.
Thanks, Ichthyic.
It may also represent a co-evolutionary arms race. Not all toxins are equally poisonous to all possible taxa of predators. A very very brief Google search unearthed this one bit from Wikipedia:
“Despite the toxins used by some poison dart frogs, there are some predators that have developed the ability to withstand them, including the Amazon ground snake (Liophis epinephelus).”
*oops* meant this to go here:
Frog pics are lovely, but what is the research the lab of Vicky Flechas is involved with?
I could easily see a species-level evolutionary advantage
no such thing.
selection works on the level of individual reproductive success.
are you suggesting these frogs are all closely genetically related, and this is a case of kin selection (and so then the aposematic coloring explained the same way)?
In any case, if people here are really interested, I’m sure there is a bit of work on predation on dedrobatid frogs in the lit to work with.
here’s a couple of fairly recent related papers to start with:
The evolution of coloration and toxicity in the poison frog family (Dendrobatidae)
Predator learning favours mimicry of a less-toxic model in poison frogs
I could easily see a species-level evolutionary advantage
no such thing.
selection works on the level of individual reproductive success.
are you suggesting these frogs are all closely genetically related, and this is a case of kin selection (and so then the aposematic coloring explained the same way)?
In any case, if people here are really interested, I’m sure there is a bit of work on predation on dedrobatid frogs in the lit to work with.
here’s a couple of fairly recent related papers to start with:*
* which will show up as soon as the links pass moderation.
The second Phyllomedusa venusta photo is making a very nice desktop background for me.
If the frogs are from Colombia, why does the URL say some-frogs-from-ecuador ?
Waxy monkey frog at an exhibit in the National Geographic museum in DD.
Sorry, DC.
Hello!
I see you have some expertise in colombian frogs. I have managed to get some frog eggs, and get them to grow, but now that they are all grown frogs, I am unable to find what species they might be. Searching the internet gives me a clue they could be Hyla cinerea, or Hyla molleri, or the like, but I am not sure. The coloring varies from brown to green and combinations of these. The eyes are not cat like, but horizontal, and they are definitely a tree frog species. I have some pictures, and could take more, but Im unsure of what to look at when identifying a frog species. I am very interested to determine the species of my frogs, and would be very thankful of any help you or you colleagues could offer!
Cheers, in advance,
Johannes