Newts and axolotls may look similar at first glance, but these amphibians actually have some key differences. If you’re looking for a quick answer, here’s the key thing to know: Newts are able to live both on land and in water, while axolotls are entirely aquatic.
In this comprehensive guide, we’ll explore what exactly newts and axolotls are, their physical features, habitat and behaviors, care requirements, and more. You’ll learn how to tell these amphibians apart and understand their unique characteristics after reading through the detailed sections below.
What Are Newts and Axolotls?
Newts
Newts are small semi-aquatic amphibians that look like a cross between a lizard and a frog. There are over 100 known newt species, most of which live in shallow ponds, lakes, rivers, and streams in North America, Europe, North Africa, and Asia. Some key facts about newts include:
- Newts have moist, porous skin and require access to water in order to breathe and prevent dehydration.
- They have a three-phase life cycle: egg – aquatic larvae – semi-aquatic juvenile/adult. The larvae resemble tadpoles and have external gills.
- Many newt species are toxic and use their brightly colored bellies to warn predators. Their skin secretes toxins that can be deadly if ingested.
- Adult newts are primarily carnivorous and eat small aquatic invertebrates like insects, worms, and snails. Their typical lifespan is 5-10 years if they reach adulthood.
Perhaps the most well-known newt species is the red-spotted newt (Notophthalmus viridescens) of eastern North America. This newt progresses through three distinct developmental life stages, a trait known as neoteny.
It can breathe through its skin and has poor vision, instead using sensory receptors on its skin to locate food.
Axolotls
The axolotl (Ambystoma mexicanum) is a type of aquatic salamander native to Lake Xochimilco in Mexico City. Some key facts about axolotls include:
- Axolotls are neotenic, meaning they retain larval features like external gills into adulthood. They never undergo metamorphosis to transition onto land.
- Their external gills allow them to breathe underwater. On land, they would suffocate due to highly underdeveloped lungs.
- Axolotls have incredible regenerative abilities – they can regrow lost limbs, heal wounds without scarring, and even reconstruct damaged internal organs and parts of their brain.
- Due to habitat loss and the introduction of invasive species, axolotls are critically endangered. There is now an extensive captive breeding program to conserve them.
- Axolotls can be a variety of colors, including brown, gray, gold, and albino. The wild type is brown with gold speckles.
Fun fact: Axolotls can smile! The ends of their mouths curve upwards to make them look like they’re grinning. This “smile” is simply their natural facial structure and not an expression of emotion. An axolotl’s smile is one of its most iconic and adorable traits.
| Newts | Axolotls | |
|---|---|---|
| Habitat | Ponds, streams, lakes | Lake Xochimilco (only natural habitat) |
| Metamorphosis | Undergo metamorphosis into terrestrial form | Remain aquatic and neotenic throughout life |
| Regeneration | Can regenerate limbs/organs to some degree | Exceptional regenerative capabilities |
| Status | Not currently threatened | Critically endangered |
To learn more about these fascinating amphibians, check out the IUCN Red List site (https://www.iucnredlist.org) and the Axolotl Care Guide at Caudata.org (https://www.caudata.org/axolotl-care.html). With proper habitat conservation and responsible captive breeding programs, hopefully both newts and axolotls can continue thriving for generations to come.
Appearance and Physical Features
Size
Newts and axolotls have very different average adult sizes. Newts are generally quite small, with most species reaching only 3-6 inches in length when fully grown. The largest newt species, like the great crested newt, may reach up to 7-8 inches.
Axolotls, on the other hand, are much larger amphibians. A full grown axolotl will reach between 9-12 inches long, making them one of the largest salamanders in the world. Their impressive size is one of the most noticeable differences between axolotls and newts.
Skin Texture and Coloration
Newts and axolotls also differ significantly in their skin texture and coloration. Newts generally have smooth, moist skin in olive, brown, or black tones to help them camouflage in forest environments. Some newt species have brighter orange or red bellies.
Axolotls have a very unique, frilly external gill structure protruding from behind their heads that gives them a prehistoric, dragon-like appearance. Their skin has a velvety texture and they come in a variety of striking colors like black, brown, gold, albino white, grey, and even purple or pink from breeding programs.
The albino morph of axolotl, with its pinkish-white skin and red eyes, is especially popular. Overall, axolotls have a distinctly different look from any newt species.
Gills
The most significant physical difference between newts and axolotls is the presence of retaining gills in the axolotl. Most salamanders lose their gills as they mature and transition from an aquatic larval stage to become terrestrial adults.
However, axolotls uniquely retain their gills and remain aquatic throughout their lifespans. They do not undergo metamorphosis like other salamanders. Newts follow the typical amphibian pattern of losing their gills as they mature.
So while axolotls breathe using feathery external gills, newts rely on lungs and lose their gills after the larval stage. This major difference in respiration defines the axolotl as a fully aquatic salamander.
Habitat and Behaviors
Where They Live
Newts typically live on land and in freshwater ponds or streams, migrating between the two habitats seasonally. The common newt (Triturus vulgaris) is widespread across Europe and parts of Asia. Axolotls are endemic to Lake Xochimilco and Lake Chalco in central Mexico, although can be found in aquariums and labs elsewhere.
These permanent larval salamanders were once abundant in the lake complex, but now wild populations are critically endangered.
While axolotls live entirely in water, newts undergo metamorphosis from the larval stage and become adapted to living on land. Terrestrial habitats used by newts include forests, grasslands and woodlands.
Some species, like the alpine newt, can be found at high elevations above 4,500 feet (1,400 meters).
Locomotion
In their aquatic larval stage, newts have external gills and tail fins for propulsion through the water. After metamorphosis they lose these features, but their skin becomes suited to respiration in both water and air.
Axolotls move through water by swimming with side-to-side undulations of their bodies, propelled by their long tails and webbed feet. They can even function on land for short periods by using an unusual “walking” motion where they whip their tails back and forth.
Diet
Salamanders are carnivorous, feeding on small prey relative to their size. As aquatic larvae, newts feed on tiny crustaceans, aquatic insects, worms and snails. After metamorphosing, they switch to feeding on land-based prey like insects, millipedes and spiders.
The diet of axolotls consists primarily of worms, insects, crustaceans and small fish. An undergraduate student’s research suggested their favorite foods were blackworms and shelled shrimp.
| Diet | Newt | Axolotl |
|---|---|---|
| Larval Stage | Small invertebrates like crustaceans and insects in aquatic habitats | Small worms, crustaceans and insects in aquatic habitats |
| Adult Stage | Land-based prey including insects, spiders and millipedes | Aquatic prey including worms, insects, crustaceans and fish |
Lifespan and Reproduction
Lifespan
Newts and axolotls have very different lifespans. Newts typically live between 10-15 years in the wild, while axolotls live between 10-15 years in captivity. In captivity, newts may live a bit longer to around 20 years.
Newts go through a complex metamorphosis, starting life as aquatic larvae before transforming into semi-terrestrial adults. This metamorphosis allows them to adapt to both aquatic and land environments at different stages of their life cycle.
Axolotls retain their larval form throughout their lives, a phenomenon called neoteny, and remain aquatic.
The axolotl’s neotenic state allows it to keep its youthful features like feathery external gills, which newts lose after metamorphosis. However, neoteny also limits the axolotl’s lifespan compared to newts that reach the adult stage.
Axolotls also have a slower metabolism and growth rate than newts, contributing to their shorter lifespans.
Breeding and Eggs
Newts and axolotls have very different breeding behaviors and eggs:
- Newts display elaborate courtship rituals, while axolotls rely primarily on pheromones.
- Newts lay eggs one at a time, while axolotls lay hundreds of eggs in long strings.
- Newt eggs are laid out of water, while axolotl eggs are laid in water.
- Newt eggs are protected by a jelly coating, while axolotl eggs are surrounded by a transparent membrane.
When breeding, the rough-skinned newt male will develop swollen vent glands on his cloaca and a crest along his back and tail to attract females. The male will fan the female with his tail and deposit a spermatophore for the female to pick up.
Axolotls largely rely on pheromones released in the water to signal breeding readiness.
Newt eggs are laid one at a time on submerged vegetation. Axolotl eggs are laid in large clusters, up to 800 at a time! The gelatinous newt egg masses cling to vegetation, while axolotl egg masses sink to the bottom.
These adaptations help each species breed successfully in their preferred aquatic habitats. Newts breed in ponds and streams, while axolotls stick to calmer lake and swamp environments.
Care Requirements
Housing
When it comes to housing, both newts and axolotls need spacious tanks with plenty of room to move around. For adult newts, a 10-gallon aquarium is usually sufficient, while axolotls need at least a 20-gallon long tank since they grow bigger. The tanks should have a secure lid to prevent escape.
You’ll also need an efficient filtration system and places for them to hide like plants, rocks and clay pots. Plants help mimic their natural environment. Always use dechlorinated water and pay attention to signs of stress like clamped fins.
Temperature and Humidity
Newts and axolotls thrive in cooler water temperatures between 60-68°F. Warmer temperatures above 74°F can cause illness or even death. Monitor and maintain appropriate water temperature with submersible heaters and chillers if needed.
Proper humidity is also vital, especially for axolotls who absorb water through their skin. Humidity above 80% is recommended. Use aquarium hygrometers to monitor moisture levels.
Feeding
Both species enjoy eating worms, including bloodworms, blackworms and earthworms, chopped up. You can supplement with feeder insects like crickets, small fish and aquatic snails. Feed them once or twice daily as much as they can eat in a 5-15 minute span.
Provide axolotls with food high in nutrients to fuel their rapid growth. Observe their eating habits and check for signs of overfeeding like bloating. Being cold-blooded, their metabolism depends much on external temperatures.
Handling
It’s vital to wash hands thoroughly before and after handling amphibians to prevent transferring contagions from your skin. Scoop gently with nets, never grab them tightly. Support newts and axolotls with both hands as they are fragile, containing soft bones and sensitive skin.
Limit handling to only when necessary. Axolotls in particular have a protective mucus coating their skin that keeps them moist, which handling can inadvertently rub off. Always avoid chemical cleansers in their environment that may irritate their skin.
| Amphibian | Avg. Size | Lifespan |
|---|---|---|
| Newt | 3-6 inches | 10-15 years |
| Axolotl | 9-12 inches | 10-15 years |
For more detailed amphibian care guides, check out websites like Caudata and Axolotl Central.
Conclusion
While newts and axolotls may appear similar at first, they have distinct differences when it comes to their physiology, habitat preferences, behaviors, and care needs. Newts are semi-aquatic and can live part of their lives on land, while axolotls must remain fully aquatic.
Both make unique and fascinating pets for experienced amphibian owners. We hope this guide gave you a comprehensive overview comparing these two amphibians.
