When you enter the exhibition of “Frogs: A Chorus of Colors”, which is open to the public until September 8 at the American Natural History Museum in New York, the first thing you will see is a pair of chubby Mexican frogs, an arboreal species (Pachymedusa Dacnicolor) endemic to Mexico. With luck you can see one of these leaf green frogs with yellow spots hanging by a toe from a branch. Like the rest of the amphibians in the exhibition they find themselves in a recreation of their natural habitat.
This museum, which enjoys a global reputation for its collection of fossils and stuffed specimens, among them dinosaur skeletons like the Apatosaurus and Tyrannosaurus Rex, houses thousands of ethnographic pieces, like the totem poles and masks of the Pacific Northwest. The enormous section dedicated to life in the oceans is presided over by a life size replica of a blue whale.
But, from time to time the museum opens its door to living specimens, and it has now arranged a captivating and fascinating exhibition of more than two hundred frogs. They range from the tiny Golden Frog from Madagascar (Mantella Aurantiaca) to the huge African Bullfrog (Pyxicephalus Adspersus). The male of the latter can measure 18 centimeters, weigh one kilo, and is able to spend months in the desert without eating or drinking, hibernating underground and emerging to mate when the rains come. The male guards and defends the eggs and the tadpoles, except when he eats them himself, since he is a cannibal from the time of his youth. Of a toad (Ceratohrys Ornata) one only sees the bulging eyes and a large mouth hidden in the hole he has dug in ground waiting motionless for some prey to eat that passes by. It is native to Uruguay and Argentina.
Perhaps the jewel of the exhibition is the nursery, where coexist some eighty small frogs from the dendrobatid family, poisonous ones, brilliantly colored which inhabit tropical regions in Central and South America. Their attractive colors of yellow, green, red, blue and orange warn predators of their toxicity, because the dendrobatids convert the poisons of the insects they consume into some of the most venomous substances in the animal kingdom. The poisoned dart from one Golden Frog (Phyllobates Terribilis) is sufficient to kill ten human beings, or twenty thousand mice, by attacking the nervous system. The indigenous Embero Choco people of Colombia, rub their hunting darts on the sides of these frogs. (Incidentally, this ethnic group is suffering a crisis of hunger and malnutrition, and their survival can be as precarious as that of these frogs, whose habitat in the humid tropical forest is rapidly being deforested.) These same toxic substances have medical uses as analgesics. By passing through three rooms the visitor can closely follow individual frogs. He or she can also listen to the croaking of frogs and toads, and see them in a country setting through videos, learning about their biology and customs.
Frogs have existed for more than 200 million years. They are to be found nearly everywhere in the world, from tropical forests to frozen tundras to scorching deserts. But according to the Global Amphibian Assessment, one third of known amphibians (88% are frogs) are threatened with extinction, and their populations are declining faster than those of birds and mammals. Since 1980, 129 species have disappeared from the face of the earth, victims of degradation and loss of habitat, the effects of climate change, and of ultra violet radiation. They are sensitive to water pollution, pesticides and acid rain. Some scientists believe that the presence of the chytrid fungus in frog populations of several continents is the chief suspect in the rapid disappearance of amphibians. Research in Central and South America has confirmed a connection between the mortality rate attributable to this skin infection and the increase in temperature due to global warming. J. Alan Pounds, a researcher at the Reserva de Monteverde in Costa Rica, has said that, “Disease is the bullet that is killing the frogs, but it is the change in climate that is pulling the trigger. Global warming is devastating the amphibians, and will soon cause uncountable losses in bio-diversity”. The decline of amphibian populations is occurring above all in the American tropics, where even in the “virgin” forests of protected areas frog species have disappeared. Like the canary in the coal mine, amphibians, because they are so vulnerable to environmental problems, are the barometer for the ecosystems they inhabit. There are believed to be about 10,000 species of amphibians on the planet, of which many are condemned to extinction before being named by human beings. In Mexico alone 198 species are in danger of disappearing.
Sana, sana, colita de rana*, si no sanas hoy sanaras manana. Unfortunately nothing appears to suggest that the frogs will be safe tomorrow nor that our planet, every day more wounded, is going to get better. They say that to cook a frog you do not throw it in boiling water because it will immediately jump out. Better to put it in cold water and raise the heat slowly, one degree at a time. Before the frog knows what is happening it will be cooked. That is what is happening to us with the earth, but the great majority of people are not aware of it. Let us listen to what the frogs are telling us.
*Sana, sana, colita de rana,si no te sanas hoy te sanaras manana. A Spanish nursey rhyme. “Get better little frog tail. If you don’t get better today, you will get better tomorrow.”