Salamander's Smile

Salamanders have teeth in both the upper and lower jaws.

 Picture from California Herps

 The larval teeth are shaped like pointed cones, while the teeth of adult salamanders are adapted to allow them to grasp prey. All of the salamander's teeth are absorbed and replaced at intervals throughout it's life.

Axolotl – The Salamander that Never Grows Up

Most salamanders are born as aquatic animals without legs or lungs and must undergo a metamorphosis to develop these essential body parts on their way to becoming land-dwelling adults. While the shape, size and characteristics of adults vary greatly over the roughly 500 species of salamanders, most undergo dramatic changes from birth to adulthood.

However, one salamander native to a few Mexican lakes never really grows up; the axolotl. Even after reaching adulthood axolotls still remain aquatic with gills and underdeveloped legs, usually resembling the larval stage of several other salamanders that eventually grow to live on land such as waterdogs.

Though there are other salamanders that keep their youthful shapes throughout life, the axolotl is the only species that is able to transform itself into a land-dwelling salamander with working limbs and lungs if conditions warrant. In most cases this will never happen, however if the animal’s water habitat starts to slowly drain and it is no longer able to submerge itself, it can transform in a matter of weeks. Scientists have also been able to induce this by injecting captive axolotls with iodine.

Though many exist in captivity, the axolotl is critically endangered in the wild. Lake Chalco, one of its two native habitats, has already been drained. The only remaining body of water in which it lives, Lake Xochimilco, has been largely drained and heavily polluted by the growth of Mexico City; though a protected area on the lake has been established to hopefully save this very unique animal. 

2011 Wrap-Up

Wow! Can you believe it’s the end of the year already? We hope you’ve enjoyed some of the fun animal facts we’ve brought you this year, and we look forward to bringing you even more in 2012.

In case you’ve missed any, here are our top five animal fact articles from the past year!


The Tiny Pygmy Jerboa – One of the world’s smallest mammals!


The Killer Whale – The true king of the sea!


The Opossum – The actor of the animal world!


Giant Chinese Salamander – 140lb amphibian!


The Vaquita – The smallest and rarest marine mammal in the world!


Happy New Year, everyone!

Image via.

The Immortal Jellyfish

It seems like stories of people searching for the fountain of youth have been around forever, and as far as animals go there are certainly plenty with much longer life spans than humans. Koi fish have been known to live over 200 years, at least one Aldabra giant tortoise lived to be 255, and a giant barrel sponge in the Caribbean is estimated to be more than 2,300 years old. However, there may be one animal that is indeed impervious to Father Time; Turritopsis nutricula, the immortal jellyfish.

Photo: Peter Schuchert

All jellyfish go through several life cycles. There are born as larvae that settle onto the sea floor or other underwater structure and develop into polyps, which look similar to a tiny octopus with its tentacles pointed up. The jellyfish buds from this polyp and begins its adult life, feeding constantly and growing quite rapidly. After reaching adult size the jellyfish will spawn, usually dying a short time after. The largest jellyfish live 2-6 months, with smaller varieties only living a matter of weeks.

So, how does the tiny (0.18”) immortal jellyfish manage to live on? The answer is a process called transdifferentiation. After the immortal jellyfish spawns as an adult, it uses this process to transform its cells back into that of an immature polyp, dropping to the sea floor and starting its lifecycle all over again. Some animals such as salamanders can use this process to re-grow limbs, but the immortal jellyfish is the only known animal that can apply transdifferentiation to its whole body, meaning that instead of dying, it becomes a newborn again; and it can repeat this process over and over.

Because these jellyfish are immortal, their population is exploding. Once native only to Caribbean waters, they can now be found in oceans all over the world.

Living Under Water

The Mexican axolotl is a salamander that lives almost all of its life in water. It keeps its tadpole-like fin and its feathery gills, while other salamanders lose them as they get older. In fact, if the Mexican axolotl does lose one of these parts, it has the ability to regenerate them throughout its adult life. This rare ability also makes it one of the world’s most frequently studied salamanders.

Don’t think small

When I think of salamanders I think of the little guys you can hold in your hand. Not so with this one. Japanese giant salamanders weigh about 55 pounds and are five feet long! The Chinese giant salamander is even larger.

Japanese giant salamanders have mottled black, brown and cream, and heavily wrinkled skin. These harmless creatures can breathe both on land and underwater.

JJ