Frog ID

[Chris]

I was out at Island 22 today and I saw this frog in a small puddle. I am wondering if anyone knows what species this is?

[merlinator]

Female Pacific Tailed Frog?

[Chris]

Thanks Roy. I looked at a few pictures and they seem to match but the one in the picture that I took doesn't have a small tail. Do they grow one?

[Deleted]

Hi folks.

Sorry, unless you really are interested in frogs, you might want to skip this message.

Whatever species this frog is, it's not a Coastal Tailed Frog (Ascaphus truei). I'm puzzled by it myself. I've sent the photo to three friends who I hope will ID it when they have time. Several species of frogs and other amphibians are now laying egg masses, so herpetologists are out busily surveying during the brief window of time this affords. Unlike frogs and salamanders, egg masses don't disappear before you get a look at them, so they can provide good data for assessing amphibians. And half of the twenty species of amphibians that are found in BC are listed (red or blue) so it's important to learn what we can about them.

Amphibians are the only vertebrates that don't have some kind of protective covering over their skin (They can absorb air and water directly through the skin) and hence they are much more vulnerable to environmental pollution than are reptiles, fish, birds and mammals. The recent world-wide nose-dive in many amphibian species should be an alarm call to us to wake up to what we're doing to our air, water, food, soil, etc.

While colour patterns might appear similar to illustrations or photos, in frogs colours and patterns can vary considerably, and body structure is more definitive for frog identification. This frog has distinct dorsolateral folds (ridges running back from behind its eyes along its back, which tailed frogs don't have. This frog has a prominent tympanum (the circular flat spot behind the eye that appears to be an "ear drum," which tailed frogs lack. This frog shows very little webbing between the toes on its hind foot, again not correct for tailed frogs.

And finally, tailed frogs are normally found in clear rushing streams on mountain slopes, not the still, silty (note the mud stains on this frog's back) habitat seen in this photo. Their respiratory system is relatively weak and they need well-oxygenated rushing water. Of course, like birds, frogs can turn up in unexpected places.

The large tympanum (bigger than the eye) would normally point to male bullfrog, but this is definitely not a bullfrog. Let's be thankful for this, as that part of the valley is still bullfrog-free.

To answer the question about the tail, most frogs live in still or slow-moving water, and frog eggs are normally fertilized externally (the male releases sperm into the water at the same time as the female releases the eggs). But if you live in fast flowing mountain streams as the two species of tailed frogs do, this would not work very well.

The tail is actually a copulatory organ (the male's cloaca protrudes outward instead of inward), making internal fertilization possible and allow successful mating in rushing water. Incidentally, tailed frog tadpoles have a sort of suction cup on their face to allow them to stick to rocks and avoid being swept away.

The general impression I get from this photo is Red-legged frog, but that species should usually show a dark mask-like area behind the eye instead of the tympanum visible in this photo. This is primarily what puzzles me. Of course, I'm the first to admit I may be quite mistaken about the whole thing.

If anyone's interested, I'll post any responses I get. Or Denis, what do you think it is?

Stan

[Gord]

I think it is a Green Frog. It's the smaller cousin of the Bullfrog from back East and let me reinforce Stan's comments at how lucky we are not to have Bullfrogs in too high of numbers out our way. There are isolated patches that Im aware of including the Royalwood Golf Course.

Stan, good info. Thanks. How true about the frogs. There are way fewer of them then what I can remember as a boy. A little scary to say the least.

[Deleted]

Yeah, it could be a Green Frog, Gord, but somehow that's still not quite right either. Green Frog should show a distinct fold running down around the back of the tympanum (similar to bullfrog), and the centre of the tympanum should normally be lighter than the rest, rather than darker than the rest as seen in the photo. In addition, the photo seems to show the "Popeye" arms of a breeding male frog (for firmly clasping the larger female), while Green Frogs and Bullfrogs won't be breeding for a couple of months yet. Red-legged, Oregon Spotted, and Treefrogs are all breeding at present.

I'm not sure where you're referring to bullfrogs being out your way. The people working on the Oregon Spotted Frog (OSF) ask us to report any bullfrogs heard or seen east of Chilliwack, or east of the confluence of the Harrison and Fraser Rivers, as the OSF's survival literally depends on keeping bullfrogs from expanding further up the valley. OSFs are down to three locations in Agassiz area, and less than 50 breeding pairs at each. They have completely disappeared from all their former locations where bullfrogs have spread into.

Bullfrogs are extremely difficult to get rid of once they get established breeding in a location, but if you hear or see them in a location where they haven't gotten established, they should be reported so we can prevent their spread. They are very destructive of native species.

Stan

[Chris]

Stan, I'm definitely interested in hearing the replies. Thanks for the indepth post as well. Myself, I do not know a lot about frogs and I learned quite a bit with what you wrote. In fact, I didn't knew there was even such a thing as tailed frogs.

[murraybrown]

Green Frog. They come in quite an array of colours much like the Pacific Tree Frog.

[Deleted]

Well, two of the three frog biologists have replied. One thinks it's a Green Frog, and one thinks it's a Reg-legged Frog. She says she's sending it to others as well, so I'll see what comes back.

Stan

[trudi]

i am sure there are bull frogs at fraser glen golf course too

[Gord]

Trudi, I think those dang frogs do get more common the further west one goes so is very likely.

Stan, Ill let Monica know about the Royalwood bullfrogs. Im sure they'll be in Cook's Marsh too sadly. Who knows where they'll travel via the ditch to find new habitat to wreck their bad habits on.

Looking more at Chris's photo, Im certain it's a Green Frog. Looks like a green mustache could be present if just a peek of green under the eye is any hint. Frogs are not my forte but I dont think Ive seen a Red-legged Frog with such a prominent ear drum. Im ready to be corrected though.

Weird colours/patterns on it. At first thought it was the camera making the parts sticking out of the water look a different colour than what's underwater. I dont think this is the case.

[Deleted]

I now have several replies -- most of the local amphibian experts that i know think it's a Green Frog, however not showing the normal fold of skin behind the tympanum, which confuses the issue.

It's a non-native frog like the bullfrog, but it's not as destructive as the bullfrog.

Stan

[Chris]

Stan, thanks a lot for looking into it. I have never seen a Green Frog look like that before but then again I don't look at too many frogs. Learned a lot though.

[Deleted]

Thanks, Chris. I always enjoy digging into something like this about nature. I always learn from it too.

I think most of us on this site are naturalists to some degree or another, and I think most naturalists are afflicted with a healthy dose of curiosity, which is a good thing. Great that we can all contribute in one way or another, and we can all learn from each other.