The Japanese giant salamander can grow up to 5 feet long , weigh 80 pounds and easily bite off a big chunk of your finger in a split second . The slimy , mottled Amphibians have remained virtually unchanged for millions of years .
Once hunted for food , the salamanders are protected as a national treasure in Japan and efforts are underway to bring forth the threatened species in captivity , according to National Geographic .
The salamanders are rarely seen , coming out only at night to take refuge in the cool stream around the foot of the mountain .
"Knowing how giant salamanders go about breeding and what conditions are necessary for this to happen when it comes to useful when considering how best to protect them in the wild , " Tim Johnson , a Tokyo - based salamander lovers who observe the creatures in the mountains told national Geographic . " The way the river modified in recent decades has made it difficult , and sometimes impossible , for them to migrate upstream to breed . "
After many attempts to give birth , a man and a woman named Daigoro called Sachiko finally managed to conceive and 500 eggs were fertilized .