The Secret of Eternal Youth? The Axolotl Has Found It!
"Eternal youth": many dream of it, but so far it seems that only the axolotl has found it. This happy-looking salamander will keep his baby face for ever and ever.
Just as a tadpole turns into a frog, so young salamander larvae are gradually transformed into adults. Except for the axolotl. This salamander species from Mexico does not undergo the usual transformation from aquatic to terrestrial animal. It does acquire lungs, but it also retains its gills and remains in the water throughout its life. An axolotl may look like a big baby salamander, but the animals do mature in the sense of being able to reproduce: they reach sexual maturity about a year after birth.
A surprising recovery
The everlasting baby face is not the only remarkable thing about the axolotl. It has another striking feature: it can repair or "regenerate" damaged tissues. How about regrowing limbs, new eyes, a heart or parts of the brain after these have been damaged? The axolotl can do it all. It retains this ability throughout its life.
No wonder scientists are very interested in the axolotl. This animal successfully mobilises the stem cells required to form bone tissue, muscle, nerves and other tissues. It can even heal after a crushed spinal column. Humans have quite a few developmental genes in common with the axolotl, so an understanding of these regenerative powers could well lead to important medical applications.
Staying young and fresh
Perhaps the axolotl's "eternal youth" and its ability to heal itself are related. In most animals – including humans – certain genes that control growth and development are "turned off" when they reach adulthood. In axolotls, on the other hand, these genes seem to remain dormant all the time, ready to be reactivated when they suffer an injury.
SOS
There are plenty of axolotls in labs or kept as pets by humans, but in the wild they are on the verge of extinction. Their Mexican habitat is shrinking and becoming polluted. In that ever-shrinking habitat, they are visited more often by their “neighbours”, species such as carp and tilapia, which eat the axolotls' food or even their young.
It is estimated that only a few hundred axolotls are left in the wild. Nature conservation organisations are therefore calling for the restoration and expansion of freshwater habitats so that the "salamander with the secret of eternal youth" can stay with us for ever and ever.