Think you know your frogs? Chances are you couldn’t tell your golden mantella from a Mexican dumpy frog. This is where Taran Grant comes in handy. The co-curator of the exhibit, Grant’s specialty is the diversity of frogs, a useful background given that the exhibit showcases more than 200 frogs from 17 countries and explores the most recent findings on the critters. Every year, he says, scientists are discovering new species just as others are becoming increasingly endangered. Grant recently spoke with NEWSWEEK’s Brian Braiker about the exhibit, which will travel to Atlanta in February before heading to the West Coast. He has been impressed by the exhibit’s “massive” turnout, he says, and guesses that people are drawn to frogs because “they’re weird enough for people to be intrigued in them, but they’re not so scary or bizarre that people are turned off by them.” Excerpts:
NEWSWEEK: What’s your favorite frog?
Taran Grant: My research is on the poison dart frogs. There are about 215 species in the family. A lot of what I do is discovering the diversity of the group of organisms. Because of the specialty I love the exhibition we put together with those.
And they’re called poison dart frogs because the indigenous people would rub darts on the frogs’ skin before shooting?
That’s it exactly. There are only three species that we know of that indigenous people have done this [with]. They actually continue to do this in Western Colombia. [It’s] the Embera Indians who do it. We have all three of those species in the central display.
If someone shot me with a dart that had been rubbed on a poison frog, what would happen to me?
Chances are you would die. It’s an extremely powerful toxin. It’s one of the most powerful toxins known in nature. It’s an alkaloid. To our knowledge [the Emberas] never used these darts in warfare–strictly for hunting. Given that they were under Spanish colonial rule for so long and they were resistant to colonial rule, we suspect that they must have used their darts in warfare. But they’re a very peaceful people.
I read somewhere that in order to test the toxicity of a frog, one licks them. Is that right?
Yeah. We certainly don’t endorse this as a general practice. But our chemosensory systems are extremely precise, and so it’s actually a very good [test] when I’m in the field–if we want to see if one of these frogs from this family is poisonous, one of the things we’ll do is touch our tongues to the back of the frog. Depending on what kind of toxins there are there you can feel a different kind of numbing effect or different taste on your tongue. With ones that we suspect are extremely toxic or ones that we know are toxic, we don’t do that.
In this exhibit you have giant frogs. You have pig frogs. You have hibernating frogs.
What we tried to put together for this exhibition is a dual message. One is the diversity of frogs, because most people think a frog is a frog is a frog. They think of frogs as being pretty much green or brown or roughly the size of a bullfrog and that they all have tadpoles, they all lay eggs in the water they all hatch out as tadpoles and they all transform into frogs. In fact, there are over 4,900 species of frogs that we know of, and their diversity of shapes and sizes and colors and lifestyles and reproductive modes [is incredible].
Reproductive modes? How so?
There are over 30 reproductive modes that are known for frogs. So anything from laying your eggs on land and transporting the tadpoles to water to having direct developments, skipping the tadpole stage altogether. There’s actually the gastric brooding frog from Australia, which actually shuts down its digestive system and swallows the eggs and lets them develop inside its stomach. There’s just a remarkable diversity. And we’re discovering more diversity constantly, so we want to highlight that.
Are any of these frogs endangered?
That’s the other side of the message. At the same time, we’re losing diversity all around the world. It’s refered to as the declining amphibian populations problem. In a lot of cases we know why: If you chop down the forest, you lose the frogs. If you divert the river, you lose the frogs. There’s basic human encroachment or development issues where we have a smoking gun for why frogs would disappear. But around the world there’s also these cases where it appears the environment is pristine–is absolutely perfect–and yet certain frog species disappear.
And you don’t know why?
We have hunches. We have a few hypotheses. We know that at least in some of these cases, there’s an infection by a fungus which at least is associated with the decline. We know that there’s a link between the frog’s decline and this fungus. What we don’t know is if that’s the ultimate cause of death or just the approximate cause of death. There are a number of ideas–it might be global warming. It might be exposure to ultraviolet radiation, it might be some sort of pollutant in the environment. Or chances are it’s probably a combination of all kinds of factors.
What is the most exciting thing in the frog world right now?
Oh, man, there’s so much!
I mean, I would imagine that in New York the only frog folks have ever seen up close is Kermit.
What really amazes me is that we are still discovering so much. It’s not so surprising when someone says, “I found a new species of ant or beetle,” because there’s so many of them and we know so little about them. With frogs, one expects that we must have a fairly complete knowledge. And yet every single year we’re discovering loads of new species. Since 1985 scientists have discovered approximately 900 species of frogs. That’s just incredible for a tetrapod [four-footed] group. And their biology is just incredibly diverse. There are frogs that live right up to the snow line in the Andes in South America. That’s a real challenge for us to understand their physiology. How can they live at such extreme temperatures? How can they be active?
How many different species are in your exhibit?
We have 24 different species, so a miniscule representation of the diversity. But what we try to do when we put together this exhibition, we wanted frogs that would do well in captivity. With that first condition we also wanted to have frogs that would be representative of the diversity of frogs. We have the ornate horned frog, which is a sit-and-wait predator. Basically it’s just a big mouth and a big stomach. It sits all day long and all night long, and it just waits for prey to walk by. When the prey comes by it lunges out. Whereas most of us think of a frog that can jump great distances like a bullfrog, this frog is absolutely sedentary. We also have aquatic frogs–frogs that never get out of the water.
So, is frog racing cruel?
We don’t do it!
