Axolotls can regenerate entire limbs, parts of their spinal cord, and even parts of their brain. These fascinating amphibians also never truly grow up — instead, they keep their youthful features throughout their lives. Scientists call this neoteny, and it’s one of the reasons axolotls are so unique in the animal kingdom.
With traits this unusual, it makes us want to dive deeper into their makeup and see what really sets them apart. That’s why we’ve put together this simple guide to axolotl anatomy — to help us better understand these extraordinary creatures we share our curiosity (and sometimes our aquariums) with.
Head’s up on axolotl parts
Starting at the head, an axolotl is made up of the:
- External gills: The feathery pink or red plumes sticking out on either side of the head. They’re not just for looks — these are how the axolotl breathes underwater.
- Gill filaments: The fine branches on the stalks where oxygen exchange happens.
- Eyes: Axolotls have lidless eyes, usually black or golden, giving them their wide-eyed, permanent “smile” look.
- Mouth: A wide mouth that curves upward slightly, making them look like they’re always grinning.
- Nostrils (nares): Tiny paired openings on the snout used for smelling, not breathing.
- Head (skull): The smooth, rounded head is broad compared to the body.
Neck and shoulders (well, sort of)
Axolotls don’t have defined necks like mammals, but here’s what you’ll find around that area:
- Throat: The underside of the head where food passes into the body.
- Shoulder region: Where the forelimbs attach, just behind the gills.
Baring the axolotl back and chest
The torso is the main body section, holding most of the important bits:
- Chest: The front part of the torso just behind the shoulders.
- Back: The smooth upper surface running from behind the head to the tail.
- Flank: The sides of the body behind the limbs.
- Belly (abdomen): The underside of the body, softer and paler.
- Costal grooves: Vertical skin folds along the sides of the body, marking the position of the ribs and aiding skin respiration.
- Lateral line: A sensory system (not visible in detail) running along the body that helps axolotls detect vibrations in the water.
Axolotl forelegs and hind legs
Like all salamanders, axolotls have four legs, but their front and back limbs differ slightly.
- Each forelimb has four slender toes.
- The elbow joint marks the bend where the upper arm meets the forearm.
- The forefoot is the hand-like end of the limb, with four toes and no claws.
- Each hindlimb has five toes, one more than the forelimbs.
- The knee joint is the bend at the front of the hind limb.
- The ankle joint lies just above the hind foot.
- The hind foot is broader than the forefoot and ends with five toes.
Bringing up the rear
The tail makes up nearly half the axolotl’s body length and is a crucial part of swimming:
- Dorsal fin: Runs along the top of the body and tail, starting just behind the head.
- ·Ventral fin: Extends along the underside of the tail, meeting the dorsal fin at the tip.
- Tail tip: The flexible end that steers them as they glide through water.
- Vent (cloaca): The opening on the underside, just before the tail starts — used for both waste and reproduction.
That covers the Axolotl anatomy basics! If you’re curious about anything else, feel free to drop a comment, reach out to us directly, or ask about joining our private Axolotl Help group on Facebook. It’s a space where we share our collective experience and tips to help you with any axolotl care questions.