Transcript of Holding and Identifying a Frog:
Andy – Ok, as I’ve said before, I find the easiest way to hold frogs is by the very end of their rear, or hind, legs so that they can’t cock to jump. So, what we want to do is identify this so everybody get their field guides out and we’re going to look for the characters that we discussed earlier and y’all are going to tell me what I’m looking at here.
Participant – Well, you’ve got that lateral, or ridge, what’s it called again?
Andy – Lateral line, lateral fold.
Participant – That goes down behind its ears.
Andy – Behind its ears. There’s one clue.
Erika – Do you remember what it’s called?
Participant – Tympanum?
Erika – Tympanum, yes!
Andy – Ok, so, do we see any brightish or neon green up under its eye. So what do you think, a frog this big, what do you think our two choices are?
Participants – Green frog or Bullfrog.
Andy – Green frog or Bull so do we see that neon green under the eyes that Green frogs have? Now Bulls can sometimes look like that too.
Participant – Not really.
Andy – I don’t really see that. It’s kinda green but not really neon green.
Participant – Um, 145 and 146.
Andy – So, the real key in this case is what that fold does. And what have we decided it does?
Participant – Curves back around behind the ear so I say it’s an American Bullfrog.
Andy – There you go. And let’s look at his stomach. So you see the splotching, the darker splotching on the venter, right? Ok, so that pretty much tells us. Ok, so now let’s look at the size of the tympanum and y’all tell me whether we’re looking at a young man or a young lady here.
Participants – Female. They’re small in size.
Andy – Yeah, smaller tympanum. Ok, so, anyone want to hold the frog?
Erika – Let’s show them the eyeball. Ok, look at his eyes, guys. See, I can push it back, see how I can just push it down in?
Participant – Does that…
Andy – Oh they have muscles that can actually pull their eyeballs in and out. So why would you want your eyeballs up like that?
Participants – So you can see above the water?
Andy – Yeah, so you can stay in the water but see what’s above the water. But why would you want to be able to pull them down?
Participants – So predators don’t see you.
Andy – Predator… let’s think about some other things. How do you reckon frogs find a lot of their food?
Participants – Under the water… Oh so they can sneak up on them.
Andy – Well, they’re gonna be nosing around in litter right? Pushing through leaves and sticks and twigs. Do you want your eyes up where they can be damaged doin that kind of thing?
Participant – Uh uh.
Andy – No, you want to pull them down. And most amphibians depend on their sense of smell as their primary sense. Ah, I work on salamanders and I had a salamander physiologist from Germany once tell me that salamanders are just giant noses. They can see but they don’t use their eyes much. And salamanders can do the exact same thing, they have telescope eyes that they can pull down when they’re foraging under leaves or under rocks in streams and things like that.
Participant – May I hold him?
Andy – Sure, so just grab right there at the end. There you go.
Participant – Oh, ok. I thought he would be more jumpy.
Andy – No, you see, if he can’t cock his legs, there’s not much he can do. Or she, excuse me, that’s a young lady.
Participant – There were three tadpoles, correct?
Participant – Four. Four small ones.
Erika – You want to try picking one up and you can see what it is?
Participant – Any of them have legs?
Andy – Do you think Green frog adults would eat Bullfrog tadpoles?
Participant – Sure.
Andy – Sure. Would an adult Bullfrog eat a Green frog or a Green frog tadpole? Sure.
Transcript of Two-Toed Amphiuma:
Erika – So what does it look like to you guys?
Participants – Eels.
Erika – It looks like an eel?
Participant – Uh huh.
Erika – But what is it really?
Participant – Salamander.
Erika – It’s a salamander. So these are the largest salamanders in North America.
Leader – They can reach sizes of up to 48 inches. This is a pretty good guy here. As you can see, well, I don’t know if you can see, but right here, see that little appendage right there?
Participant – Yeah.
Leader – With two little itty bitty toes? Can y’all see that?
Participant – Yeah.
Leader – Can everybody see that?
Erika – He’s got two back here and two up front.
Leader – See that little foot right there? That little itty bitty foot?
Erika – And this guys called a two-toed amphiuma. So like I was saying earlier, he’s got six rows of teeth and they’re all segmented so they’re broken up, so he may have two on this side, two on this side, and two in the middle but they’re all broken up.
Leader – So what would you think that these guys eat?
Participant – Small fish.
Leader – Small fish, yeah. What else would live back in this area that they might like to eat?
Participant – Frogs.
Leader – Frogs? Yeah. With six rows of teeth they can pretty much eat anything, right? Their main forage is usually crayfish. You know, crayfish have shells but it’s nothing for them to crunch through those shells with six rows of teeth.
Erika – These guys are mostly active at night. When there’s heavy, when there’s a lot of heavy rain they can cross over roads to the other side and they’ll go to, like, a ditch or something.
Leader – How do you think these guys breath?
Participant – Lungs.
Leader – Lungs? Maybe, anybody else got an idea?
Participant – Skin.
Leader – Skin… What do you think, Emily?
Emily – I don’t know.
Leader – You don’t know?
Emily – No.
Leader – These guys can actually breathe all three ways: they can breathe through their skin, they also have a lung so they can gulp air and breathe like we do, and they also have internal gills. So they’re kinda the ultimate survivor, they can survive in just about any kind of environment.
Erika – So not a lot is known about their early stages of life because not a lot of people catch these things. They’re really abundant in areas but they’re just not caught a lot. So a lot isn’t known about their early stages of life. We do know they can lay anywhere from 10 up to 200 eggs and they usually lay in, like, damp places.
Transcript of Traps and Experimental Design:
Andy – So, at each site in this particular project, we have three different kinds of traps. One of them is a leaf-pack trap and that’s pretty much a passive trap where we put the packs in the water and macroinvertebrates and certain kinds of salamanders and amphibians will crawl in there for cover during times of the day when they’re not active. And then they can hide in there and so then we can pull those little packs out and see what we’ve got.
In addition, at each site, we have two minnow traps, one of which we bait and we bait with sardines, but you’re free to try whatever you’d like, and the other minnow trap is unbaited. We can attract a variety of different kinds of things in those baited and unbaited traps. We regularly get crayfish, we get adult and tadpole frogs, we get adult and larval salamanders in those sorts of traps. So we can talk a little bit about food chains and who eats who and energy processing and stuff like that. Mostly we try to emphasize the numbers of animals that you can find in streams of this size that you can jump across.
We can then talk about experimental design, controlled experiments and why controls are important. Then we let the students think a little about which of our minnow traps has a manipulative variable and which of it has a control, why those work the way they do. And the interesting thing about it is we get varied results on that, our results are not necessarily clear cut. The main conclusion that I have come to over three or four years is that frog tadpoles seem to be attracted to baited traps and I can’t tell much difference between any of the other animals. They seem to go into the other two kinds of traps almost equally.
Ok, so that’s a little bit about experimental design.
Transcript of Minnow Traps:
Erika – You’ve seen them? So you guys know what they look like?
Participant – Yeah.
Erika – So who wants to give me a brief description? Go ahead Emily.
Emily – I don’t know, they can swim into it but they can get out.
Erika – What shape does it tend to be?
Participant – Like a cone.
Erika – Like a cone? Ok, so, why can they swim in and not out?
Emily – The shape of it…
Participant – It kinda funnels them in.
Erika – It funnels in, that’s right.
So this is what your basic minnow trap is gonna look like. I know that they have different sizes for these, you can get ones with bigger holes and ones with smaller holes. What do you notice that we put in all our traps that you’ve seen?
Participant – A bottle so it floats.
Erika – We put a bottle so it floats. Why do we want it to float?
Emily – So that they can get air.
Erika – So they can get air? Ok.
Participant – So it’s not sitting on the bottom.
Erika – So it’s not sitting on the bottom, ok. And we don’t want anything in here that needs air to drown, right? Ok so when you set a trap like this, how often do you want to check it?
Participant – Every day.
Erika – Everyday, how many times a day do you think?
Participant – Probably twice.
Erika – Once or twice a day, why do we want to do that?
Participant – To make sure that, if you do have something in there that you take it out.
Erika – Ok, that’s right.
Ok, what sorts of things do you think we would catch in this? What kind of amphibians? Or maybe not even amphibians, other things too.
Participant – Salamanders.
Erika – Salamanders, ok.
Participant – Amphiumas.
Erika – Amphiumas, ok. Anybody else? What do we hear calling every night?
Participants – Frogs.
Erika – Frogs, ok. And then what is this thing, it would normally be alive?
Participant – Fish.
Erika – A fish. So fish, what other kinds of things could we find in here?
Participant – Snakes.
Erika – Ok, snakes. And what is this thing here?
Emily – A spider.
Erika – Spiders, ok, so we can find bugs. So there’s a variety of things you can find in here and there are a bunch of different ways that you could bait your traps. You can put sardines like we did, we stole your idea Christine. So you can put sardines or you can put chicken, we put chicken in one. Last year we did glow sticks. So you can use a bunch of different kinds of things to try…
Participant – Glow sticks?
Erika – Mm hmm, we were trying to see if the light attracted…
So this is going to be what your basic minnow trap will look like so, when you’re done, and you don’t see anything in it. You normally wanna roll it around like this, make sure you look at it from all sides and you’re not missing anything. And you’ll just throw it back in the water like this.