If you’re anything like me, the first image that comes to mind when someone mentions an axolotl’s head is the striking fan of feathery gills extending gracefully from each side. While these gills are certainly the most eye-catching feature, there’s much more to an axolotl’s head than meets the eye. It contains a range of fascinating structures, many of which are vital to the animal’s survival—and all of which are worth understanding if you keep axolotls or simply admire these unique salamanders.
Like in all animals, the head is made up of external features that are visible to us and internal ones hidden beneath the surface. To fully appreciate the axolotl’s head, we’ll explore both—starting with the external features.
External Features
Externally, an axolotl’s head comprises of:
- Eyes: Most axolotls have round, dark eyes with shiny golden or iridescent rings around the iris. Unlike many animals, they lack eyelids, so their eyes are always “open.” This makes them sensitive to bright light.
- External Gills: This is probably the most iconic part of the axolotl’s head. Three feathery stalks (rami) sprout from each side of the head, just behind the eyes. The gills are covered in tiny, thin filaments (fimbriae) full of blood vessels that allow the axolotl to breathe underwater.
- Mouth: Axolotl mouths are wide and curved into a natural “smile.” They don’t have true teeth like humans; instead, they have tiny, rudimentary teeth used more for gripping than chewing.
- Nostrils (Nares): These are small paired openings on the top of the snout that help them smell underwater. These are not used for breathing, since axolotls rely on their gills and skin for oxygen exchange.
- Skin: The skin on their head is smooth and slimy, covered in a protective mucus layer. This helps with gas exchange and protects them from infections.
Internal Features
Naturally, an axolotl’s head contains many internal structures that could take pages to fully explore. For now, let’s focus on the key ones you should know about:
- Brain: Like other salamanders, axolotls have relatively simple brains compared to mammals, but they still control movement, feeding, and sensory processing.
- Sensory Organs – Apart from their eyes and nostrils, axolotls rely heavily on their lateral line system, a set of sensory organs along the head and body that detects vibrations and movements in the water.
- Gill Slits and Rakers: Hidden beneath the external gills are slits lined with gill rakers. These help filter particles out of the water so food doesn’t get trapped in the gills.
- Jaw Muscles: Strong enough to create suction when they snap their mouths open, pulling in prey like worms, insects, or small fish.
Head Shape and Variation
Not all axolotl heads look the same. Some appear flatter, while others look rounder or broader. These differences can be due to:
- Genetics – Just like humans, axolotls inherit traits that affect the shape and width of their heads.
- Growth and age – Juveniles often have proportionally larger heads compared to their bodies. As they grow, the head may appear narrower or broader depending on body size.
- Sex differences – Males often have slightly wider, broader heads compared to females, though this is not always an absolute indicator of sex.
Swelling and Puffiness
If you spend time around axolotl enthusiasts, you’ll often hear questions like, “Why does my axolotl’s head look swollen or puffy?” The short answer is: A swollen or puffy head can sometimes indicate health concerns. Possible causes include:
- Infections (bacterial or fungal) leading to localized swelling
- Injury from tank decor, rough handling, or tank mates
- Water quality issues causing stress and fluid retention
- Natural differences—in some cases, what looks like puffiness is just the way the skin folds around the head and gills
Regeneration and Healing of the Head
Another question axolotl keepers often ask is whether these amphibians can regrow their heads. While they cannot regenerate an entire head if decapitated—since that would mean the animal has died—they are remarkable healers. Axolotls can repair damaged tissue in the head, including skin, bone, parts of the jaw, and even sections of the brain. The speed and success of healing depend on factors such as the size of the injury, the axolotl’s age and overall health, and the quality of its environment. Minor head injuries usually heal well with proper care, although some scarring or slight changes in shape may remain.
Quick FAQs about Axolotl Heads
1. Why does my axolotl keep bumping its head into the glass?
Head bumping is a fairly common behavior in axolotls and usually relates to how they perceive their environment. Because axolotls have poor eyesight and rely more on smell and vibrations, they may not recognize that the glass is a barrier. Sometimes they confuse their own reflection for another axolotl, while in other cases restlessness or stress from poor water conditions can make them pace and bump against the tank walls. Adding visual barriers, improving water quality, and ensuring the tank is large enough often helps reduce this behavior.
2. What are the bumps or lumps I see on my axolotl’s head?
Small bumps on an axolotl’s head can happen for several reasons. They may be minor injuries in the process of healing, harmless cysts or growths, or even natural variations in skin texture. In rare cases, parasites or infections can also cause lumps to appear. Any sudden or fast-growing lump should be monitored closely, and if it doesn’t go away on its own, consulting a vet is the safest choice.
3. Do bumps on the head always mean illness?
Not necessarily. As aforementioned, many small bumps that appear on an axolotl’s head are harmless, and may just be healing spots from minor scrapes, benign cysts, or natural variations in skin texture. However, it’s important to keep an eye on them. If a lump grows quickly, changes color, looks inflamed, or is accompanied by other signs of stress like loss of appetite or unusual behavior, it could be linked to infection, parasites, or another health issue. In those cases, seeking veterinary advice is the safest option.
4. Are male and female axolotl heads shaped differently?
Yes, though the differences can be subtle. Males tend to develop wider, broader heads with a more pronounced jawline, while females usually have narrower, smoother heads. These distinctions become clearer as axolotls reach adulthood, and are often more reliable when combined with other sexing features such as body shape and cloaca size.
5. Why does my axolotl’s head look different from others?
It’s normal for axolotls to have slight differences in head shape. Genetics play a big role—some axolotls are born with broader, flatter heads, while others have narrower or more rounded ones. Age is another factor, since younger axolotls often have smaller, less defined features that become more pronounced as they mature. Sex also influences head shape; males usually develop wider, stronger-looking heads, while females often have smoother, slimmer profiles. These variations are natural and don’t usually indicate any health concerns.