Axolotls (scientific name: Ambystoma mexicanum) are a species of salamander native to freshwater lakes in Mexico City, Mexico. Over the course of the past few decades, axolotls have become very popular exotic pets. Their cute looks, ability to regenerate limbs, and unusual life-cycle have a lot to do with that.
The life cycle of axolotls is unusual in comparison with other amphibians. Indeed, axolotls are neotenic creatures and reach adulthood without undergoing metamorphosis. As a result, axolotls permanently retain certain larval features such as their external gills, tail fins, large heads, or larval coloring.
In this article, we will take a closer look at what makes the life cycle of an axolotl so special, and answer a number of related questions. Keep on reading to find out more!
Table of Contents
- Axolotl Life Cycle
- Axolotl Growth Rate
- Can Axolotls Go Through Metamorphosis?
- How Long Do Axolotls Live? (Axolotl Lifespan)
- Frequently Asked Questions
Axolotl Life Cycle
Generally speaking, most amphibians are born in an aquatic environment where they spend the initial stages of their lives. Eventually, they undergo metamorphosis and become fully developed, land-dwelling adults. This biphasic lifestyle is characteristic of amphibians.
Salamanders tend to display diverse developmental patterns across a range of species. Some species undergo a radical transformation from larvae to terrestrial adults. Other species, such as the salamander never go through metamorphosis, retain certain larval features, and remain aquatic creatures throughout their lives.
The typical life cycle of a salamander has 3 different stages: egg, larva, and adult.
How Many Stages Are There in The Life Cycle of An Axolotl?
Excluding conception and death, there are 3 distinct stages in an axolotl’s life cycle. Each stage has its own “sub-stages”, which we will also cover below.
If you’re interested in learning more about how axolotls reproduce, check out our article about axolotl reproduction.
Stage 1: Fertilized Axolotl Egg
The first stage of an axolotl’s life is the fertilized egg. The fertilized axolotl eggs go through several stages of growth, outlined below.
Embryo
The first stage of a fertilized axolotl egg is the embryo, which is essentially a single cell.
At this stage, the unborn animal is in the earliest phases of growth and its basic structures are being formed. The cell is protected by an outer layer of translucid, gelatinous substance. At this point, the egg measures approximately 2mm in diameter.
Clump of Cells
As the embryo develops, what was once a single cell goes through numerous rounds of cell division to form a growing clump of cells.
The clump of cells develops emerging features such as a body and a head, and increasingly resembles an axolotl larva. Right before it hatches, the egg now measures approximately 10mm in diameter.
Stage 2: Axolotl Larva
After approximately 2 weeks (15 days), the axolotl larva hatches from the egg. The larva stage can itself be broken down into 3 “sub-stages”, depending on the absence or presence of limbs.
Limbless Larva
At this stage in the axolotl life cycle, the axolotl hatchling is limbless, has a long tail, and is translucid to the point where its internal organs are visible through its skin. At this stage, the larva’s gill buds will begin to grow. It almost resembles a small fish.
Larva With Front Limbs
After 8 to 9 days, when the axolotl larva reaches approximately 2 cm in length, it will begin to grow two front limbs or legs (forelimbs). The front feet have 4 toes. The gill buds will already have started to grow into the feathery external gills axolotls are famous for.
By day 15, as the axolotl larva reaches approximately 2.5 cm, the two front limbs should be fully grown and the hind leg buds should be showing.
Larva With Front & Back Limbs
By day 30 or so, when the axolotl larva reaches approximately 4 cm in length, it will have all 4 limbs: two front limbs with 4 toes on each foot, and two back limbs (hind limbs) with 5 toes on each foot.
This phase is often referred to as the juvenile phase. Juvenile axolotls will have most of the physical features of adult axolotls except for their size and weight. Moreover, juvenile axolotls are not yet capable of reproducing.
Stage 3: Adult Axolotl
An axolotl is said to reach adulthood when it becomes sexually mature. Axolotls can reach sexual maturity anywhere from 6 to 12 months, with certain individuals reaching adulthood as late as 18 to 24 months.
Gender
When axolotls reach sexual maturity, it becomes much easier to tell what gender they are: female or male. We also have a dedicated article to help you sex your axolotl.
Adulthood – and in particular the metamorphosis stage – is really where axolotls begin to differentiate themselves in terms of development when compared with other salamander species.
Neoteny
Axolotls are a neotenic species. This means that axolotls retain many of their juvenile characteristics into adulthood.
Indeed, whilst most amphibians will go through a developmental stage called metamorphosis, axolotls don’t. This pedomorphosis results in stunted growth.
During metamorphosis, most salamander species will lose their gills and elongated dorsal fins, the proportions between the size of their head and the rest of their bodies will change, and they will eventually leave the aquatic habitats they were born in to become predominantly terrestrial creatures.
Axolotls on the other hand will live underwater for their entire lives.
How Long Does It Take for An Axolotl to Fully Mature?
It typically takes 6 to 12 months for axolotls to fully mature, i.e. reach sexual maturity and acquire the ability to reproduce. In certain cases, it may take longer (18 to 24 months), but this is relatively uncommon.
Axolotl Growth Rate
| Life Cycle Stage | Start Date | Duration | Size |
| Stage 1: Fertilized Egg (Embryo) | Day 1 | N/A | 1/16 inch 2 mm |
| Stage 1: Fertilized Egg (Clump of Cells) | Day 1 | 15 Days | 1/16 inch – 3/8 inch 2 mm – 10 mm |
| Stage 2: Larva (Limbless) | Day 15 | 15 Days | 3/8 inch – 1 inch 10 mm – 2.5 cm |
| Stage 2: Larva (Front Legs Only) | Day 30 | 15 Days | 1 inch – 1 1/2 inches 2.5 cm – 4 cm |
| Stage 2: Larva (Front & Back Legs) Also referred to as “Juvenile” | Day 45 | 4.5 Months (At least) | 1 1/2 inches – 8 inches 4 cm – 25 cm |
| Stage 3: Adult | Month 6 (At the earliest) | 5 to 15 years (wild). 10 to 20 years (captive). | 8 inches – 10 inches 25 cm – 30 cm (when fully grown) |
Can Axolotls Go Through Metamorphosis?
It is very rare for an axolotl to undergo metamorphosis in the wild. However, metamorphosis has been induced in an experimental setting.
What Causes Axolotl to Morph?
To transition from aquatic-dwelling animals to terrestrial-dwelling animals, salamanders must undergo metamorphosis. During metamorphosis, most salamanders will typically lose their external gills and long dorsal fins. Their lungs will also develop to allow them to breathe air and therefore live on land.
Metamorphosis requires a thyroid hormone called thyroxine to activate the regression of larval traits and promote the development of adult traits. The production of this hormone is itself stimulated by iodine.
However, the lack of iodine in the axolotl’s natural habitat explains why they have evolved to not undergo metamorphosis.
Whilst metamorphosis is rare in nature – but not impossible – it has successfully been induced experimentally by scientists. As outlined in the study published online in February 2014, researchers added the hormone thyroxine to the rearing water of axolotls to induce metamorphosis.
What Do Axolotls Metamorphose Into?
When they undergo metamorphosis, axolotls transform into morphed adults which resemble adult tiger salamanders or spotted salamanders. They lose their external gills, and dorsal fin and their skin become darker.
How Long Do Axolotls Live? (Axolotl Lifespan)
The lifespan of an axolotl will tend to vary depending on whether or not they live in the wild or in captivity.
How Long Do Wild Axolotls Live? (Axolotl Lifespan in The Wild)
The typical lifespan of an axolotl in the wild is 5 to 15 years.
On average across a population, axolotls tend to have shorter lives in the wild than they do in captivity. Indeed, wild axolotls are not cared for as captive or pet axolotls are, the living conditions in their natural habitat are now sub-optimal and deteriorating, and they are subjected to predation, unlike their domesticated cousins.
How Long Do Pet Axolotls Live? (Axolotl Lifespan in Captivity)
The typical lifespan of an axolotl in captivity is 10 to 20 years.
On average across a population, axolotls tend to live longer in captivity than they do in the wild. Indeed, captive or pet axolotls tend to live in optimal conditions and are protected from predators. With favorable genetics and if very well cared for, certain axolotls may even live up to 20 years.
How Does the Axolotl Lifespan Compare to Other Salamanders?
The table below summarizes how the longevity of an axolotl compares with that of other salamanders.
As you will see, the axolotl’s life expectancy in the wild is average. It’s not the salamander with the shortest life expectancy amongst the creatures reviewed below (Slimy Salamander; 4 – 8 years), nor the longest life expectancy (50 – 70 years; giant salamanders).
| Salamander Species | Longevity in the Wild |
| Slimy Salamander | 4 – 8 years |
| Fire Salamander | 6 – 14 years |
| Marbled Salamander | 8 – 10 years |
| Axolotl | 5 – 15 years |
| Tiger Salamander | 10 – 16 years |
| Yellow-Spotted Salamander | 15 – 20 years |
| Blue-Spotted Salamander | 15 – 20 years |
| Hellbender Salamander | 15 – 25 years |
| Giant Japanese Salamander | 50 – 70 years |
| Giant Chinese Salamander | 50 – 70 years |
Frequently Asked Questions
Can Axolotls Live Forever?
Axolotls cannot live forever. Due to their regenerative abilities, many people think that they can simply maintain and repair themselves forever and never get old or sick. However, this is not true and all axolotls end up dying, eventually. In the wild, axolotls tend to live 5 to 10 years. In captivity, axolotls tend to live longer – from 10 to 15 years.
Can axolotls live for 100 years?
Axolotls cannot live for 100 years. To be more precise, there hasn’t yet been a documented case of an axolotl reaching the 100-year milestone.
Do Axolotls Turn Into Salamanders?
Axolotls do not turn into salamanders. Axolotls ARE salamanders. Or, a species of salamander to be more precise.
How Old Is a 4 Inch (10 cm) Axolotl?
A 4-inch or 10-cm long axolotl would typically be anywhere from 4 to 5 months old.