when we lose species, thth are gone fororever. we c cannot buy them back, nor n we discover these potential secrets that could be lifesaving. if people understood that better, i think they would behave very differently. >> today, amphibians are one of the most threatened species on earth. nearly one-third are in dangeger g going extxtinct. >> they're very sensitive to changes in their environment. poisons, of climate change, habitat destruction. if you have never held an end to be in your hand, you know that they feel moist and clammy. that is because they breathe through their skin. in order to do that, the skin is very thin and moist. it is used in of fact as a lung to some extent. many of them breathes through their skin exclusively. there are some animals that only breeze through their skin. they also take up water through their skin. as they do this, because they do not have a very effective barrier with the outside theyronment, they cannot -- can't absorbable lot of the toxins a and chemicals into ther bodies very readily. t