[kellyhound]

The Chinese giant salamander (Andrias davidianus) is the largest living amphibian in the world, growing up to 5.9 feet, 1.8 meters long and weighing up to 110 lbs, 50 kg.

They lack gills as adults and absorb oxygen directly through their porous, wrinkled skin.

They have very poor eyesight due to tiny, lidless eyes, but their bodies and heads are covered in special sensory nodes that detect water vibrations to locate prey.

As ambush predators, they use a powerful vacuum suction feeding method to snap up prey in less than 50 milliseconds. They primarily feed on fish, frogs, crayfish, worms and insects.

Females lay hundreds of stringed eggs in underwater cavities, which are then guarded and fiercely defended by the males for months without eating.

Listed as Critically Endangered on the IUCN Red List, with wild populations declining by over 80%.

Overexploitation for luxury food and traditional Chinese medicine, habitat destruction, water pollution and genetic pollution from farmed salamanders released back into the wild.

Recent genetic studies show that what was once considered a single species (Andrias davidianus) actually comprises multiple distinct cryptic lineages and species, such as the South China giant salamander (Andrias sligoi).

The incredible longevity of the Chinese giant salamander (living 60 to over 100 years) comes down to a combination of an incredibly slow lifestyle, unique evolutionary adaptations and an environment that keeps their bodies running at a minimum speed.

Like all amphibians, giant salamanders are ectothermic (cold-blooded). They live in permanently cold, fast-flowing mountain streams. Because their environment is chilly, their internal chemical reactions move at a crawl. They consume very little energy just to stay alive, which significantly reduces the natural "wear and tear" on their cells over time.

Because their metabolism is so slow, they can survive for months—and sometimes over a year without eating a single bite of food.

When food is scarce, their livers dynamically up-regulate specific proteins to burn stored fats and protect their organs. This incredible resilience protects them from starving during harsh seasons or periods when prey is sparse.

Unlike humans, who constantly exert energy to breathe, the Chinese giant salamander absorbs oxygen passively through its skin. Its deeply wrinkled, baggy flesh maximizes the surface area exposed to oxygen-rich water meaning they can remain completely still at the bottom of a river for days, absorbing oxygen without expending the metabolic energy required to surface or pump lungs.

In a healthy, natural ecosystem, an adult Chinese giant salamander has no natural predators. Because they are the apex predators of their underwater caves and streams, they are rarely killed by other animals.

Giant salamanders belong to an ancient lineage that retains powerful regenerative capabilities. If they are injured by moving rocks or territorial fights, they have the ability to perfectly regrow damaged skin, muscle, and even bone. This highly efficient cellular repair mechanism prevents minor wounds from becoming fatal infections, effectively extending their lifespan.

Just like a tree grows rings each year, a salamander’s bones develop concentric growth rings (called lines of arrested growth) due to seasonal shifts in their metabolism.

Scientists gently take a tiny bone sample (often from a digit or a clipped toe during fieldwork) or examine bones from deceased specimens. By cutting a cross-section of the bone and looking at it under a microscope, they can count the annual rings to pinpoint the animal's exact age.

Giant salamanders genetically diverged from all other amphibians. They shared the planet with dinosaurs like the Stegosaurus and Brachiosaurus. These salamanders survived by staying safely tucked away in the deep, shielded environments of underground river caves after a massive asteroid hit Earth.

Outwardly, they look nearly identical to fossilized imprints left behind by their ancestors during the age of the dinosaurs.

Their "cousin" is the North American hellbender that typically lives for 25 to 35 years in the wild.

Surprisingly, humans already share many of the exact same genes that salamanders use to regrow limbs and bones. The difference is a matter of gene settings as when humans are injured, our bodies panic and trigger rapid scarring to stop bleeding and when a salamander is injured, it suppresses scarring and triggers a blastema (a localized construction zone of stem cells that perfectly rebuilds muscle, bone and nerves).

Researchers use gene-editing tools like CRISPR on salamanders (specifically the axolotl) to isolate master genes like SP8 and Shox, which dictate bone growth and structural length.

By taking the chemical signals controlled by these salamander genes and delivering them via viral gene therapy to mice with damaged digits, scientists successfully forced mammalian bones to regrow.

Scientists are leveraging these trials to design targeted drug therapies. The goal is to apply a specialized molecular gel or cellular signal to a human amputee or severe bone fracture, forcing adult human bone and connective tissue cells to forget their age, revert to an embryonic state, and regrow perfectly.

[Mr.NoCredit]

Amazing creature. Interesting about how they regrow limbs and even more so that scientists are trying to create drugs for humans to regrow lost limbs. That would be incredible if actually accomplished and would be monumental for a pharmaceutical company. I would imagine the cost to be exorbitant. Still pretty cool science.

[William May]

I was going to make a joke about how you could look at MY HUGE CHINESE SALAMANDER, until I read all the interesting info about regrowing damaged limbs!

No telling WHAT medicine will be able to do in another 50 years!

[yah]

Originally Posted by kellyhound ↗

They lack gills as adults and absorb oxygen directly through their porous, wrinkled skin.

I also absorb oxygen directly through my porous, wrinkled skin. It's one of the benefits of getting older.

[kellyhound]

Originally Posted by yah ↗

I also absorb oxygen directly through my porous, wrinkled sack. It's one of the benefits of getting older.