Snake lumps and swellings: what a bump along the body means, and how to log one

Quick answer

Run the whole snake through your hands on a schedule, and you will find lumps while they are small. Snakes are the easiest pet to examine completely and the hardest to read when you do not know what sits where.

A snake's organs are arranged in a predictable order along its length. That means the single most informative thing about a lump is not its size or its firmness but where along the body it is, expressed as a fraction of the distance from snout to vent.

A smooth oval swelling a third of the way down a snake that ate four days ago is a meal. The same swelling in the same place in a snake that has not eaten for two months is something else entirely, and the difference is the history, not the lump.

• Measure position as a fraction of snout to vent length, not in centimetres from wherever you started.
• Photograph every lump beside a ruler or a coin, from the same angle, with a date.
• Firm, discrete swellings under the scales in snakes are usually abscesses, and snake pus is solid, so they never burst and drain.
• Two swellings arranged symmetrically in the rear half of a female snake are often follicles or eggs.
• Never squeeze, lance, soak or apply a cream to a lump under the scales.

Decide in 60 seconds

Why position tells you most of the answer

A snake is a tube with the organs laid out along it in sequence, and unlike a mammal they are not stacked in a single cavity where anything could be anywhere. The heart lies in the forward portion of the body, followed by the lungs, then the liver, then the stomach, then the small intestine, with the kidneys well toward the rear, the colon behind them, and the vent, scent glands and, in males, the inverted hemipenes in the tail base.

The exact proportions vary between families, so a python is not laid out identically to a colubrid, but the order never changes. That is why a vet's first question about a lump is always where it is.

To make your description usable, measure it as a proportion. Run a soft tape or a piece of string along the snake from the tip of the snout to the vent, note that number, then note the distance from the snout to the lump. Report it as a fraction. "One third of the way from snout to vent" is a useful clinical statement. "About twenty centimetres down" is not, because it depends entirely on the size of the snake.

What each kind of lump usually is

Smooth, oval, firm, mid body, after a meal. A food bolus. It should soften, flatten and move toward the tail over the following days and be gone within the normal digestion time for the species and temperature. A bolus that stays put for over a week suggests the snake is too cool to digest, or that something is obstructing.

Firm, discrete, under a scale, sometimes with the scales lifted or discoloured. Almost always an abscess. In reptiles these form as solid caseous masses walled off by the immune system, so they cannot be drained. They are treated by surgical removal and by finding the source, which is often a rodent bite, a scale injury or a spread from mouth infection.

Two swellings in the rear half of the body, arranged symmetrically, in a female. Ovarian follicles or eggs. Normal in a reproductively active female, and abnormal if she is straining, off food for an extended period, or if they persist without being laid.

A firm swelling just in front of the vent in a male. Impacted hemipenes or hardened plugs of secretion. Sometimes visible as swelling on one or both sides of the tail base. It needs veterinary attention because impaction leads to infection and to tissue damage.

Soft, diffuse, pitting swelling along the ventral surface. Fluid accumulating in the body cavity or under the skin. This points at heart, liver or kidney disease, or at severe infection, and it is a medical rather than a local problem.

Generalised swelling of the whole rear body with reduced or absent faeces. Constipation, impaction or an obstruction. Common in snakes kept too cool, dehydrated, or on a substrate they ingest.

Hard, irregular, along the spine. Spinal deformity from old trauma, from metabolic bone disease, or from a spinal disease that thickens vertebrae. Often accompanied by kinks or an altered movement pattern.

Soft, mobile, symmetrical, throughout the body in a heavy snake. Fat deposits. Common in captive snakes that are fed too often, and it is a body condition problem rather than a mass.

Swelling with discoloured, blistered or lifting scales. Blister disease and thermal burns both present this way. Both point at the enclosure: humidity and hygiene for one, an unguarded heat source for the other.

A ring around the tail with a swollen or dark tip. Retained shed forming a tourniquet. The tissue beyond it dies. Do not pull it off, because the underlying skin may already be compromised. This needs veterinary attention and it needs the enclosure humidity investigating.

Neck or throat swelling. Regurgitated or lodged prey, an oesophageal problem, infection tracking from the mouth, or respiratory disease. Any of these with breathing changes is urgent.

Jaw or head swelling. Infectious stomatitis tracking into the bone, an abscess, or metabolic bone disease. A swollen jaw in a snake that is also not eating is a mouth problem until proven otherwise.

Slowly enlarging, painless, in an older snake. Neoplasia is a real possibility and needs a sample, not a period of observation.

The measure log

Keep the scale, the ruler and the log together, and use them on a fixed day. A lump that has not changed in a month is a different clinical problem from one that has doubled, and only a record can tell you which you have.

Record the same fields every time, on the same day of the week.

Two photographs a fortnight apart, taken the same way with the same reference object, tell a vet more than any verbal description.

What changes the interpretation

Look at the whole animal while you have it out: eyes, scales, vent and the way it moves. A lump plus a clear eye, a clean vent and normal movement is a different problem from a lump plus retained spectacles and a sluggish snake.

Feeding history. The single most important context. Know the date of the last meal, the prey size, and whether the snake has regurgitated.

Sex and season. Reproductively active females develop follicles seasonally. Males in breeding condition are more prone to hemipenal problems. Both change what a rear body swelling is likely to be.

Species and body plan. Boids and pythons carry more fat and more body mass, so both fat pads and internal swellings feel different from those in a slender colubrid. Proportional organ positions differ slightly between families.

Age. Young snakes present with growth related and husbandry related problems. Older snakes present with tumours and organ disease.

Body condition. An obese snake has fat where a lean one has none, and it also has fatty change in the liver that affects everything else.

Temperature and humidity history. Cool enclosures cause retained food and constipation. Low humidity causes retained shed and constriction rings. Unguarded heat sources cause burns that look like swellings.

Enclosure hygiene and prey. Live prey bites are a leading cause of abscesses. So are sharp decor items and rough substrates.

Recent shed. A snake in shed looks and feels different, and lumps are harder to assess. Note where the snake is in its cycle.

What the vet will do, and what to bring

A reptile vet will palpate the whole body, locate the lump against the expected organ position, and then usually image it. Radiographs show mineralised material, eggs, foreign bodies and skeletal change. Ultrasound distinguishes fluid from solid and shows organ structure. A fine needle sample with cytology often gives an answer on the day for an abscess or a tumour.

The reason to go rather than to wait is that the two commonest firm lumps, abscesses and tumours, both get harder to treat with time and neither resolves on its own.

What never to do

Never squeeze, lance or attempt to drain a lump. Reptile abscesses are solid and squeezing spreads infection into surrounding tissue.

Never apply a hot compress to bring a lump to a head. It will not, and burns are a real risk on a snake that cannot move away.

Never apply human antiseptic creams, essential oils or drawing ointments under scales.

Never pull retained shed off a swollen tail tip. The tissue underneath may be dying and pulling causes an open wound.

Never feed a snake that has a firm mid body lump and a history of regurgitation until it has been seen. You are loading a gut that is already failing to empty.

Never assume a lump is food without a feeding date that supports it.

Never leave a lump for months because it is not bothering the snake. Snakes conceal illness thoroughly, and growth rate is what determines the outcome.

Never introduce a snake with an undiagnosed swelling to the rest of a collection.

When to get help

Go the same day for a swelling with breathing difficulty, for a swollen or dark tail tip with a constricting ring, for a swollen jaw with a mouth that will not close, or for a snake that is straining and producing nothing.

Book an appointment this week for any firm discrete lump, any lump with lifted or discoloured scales, any lump that has grown between checks, any swelling with regurgitation or weight loss, and any symmetrical rear body swelling in a female.

Bring the log, the photographs, the feeding history and your temperature readings. In snakes, the history usually narrows the diagnosis before the animal is examined.

A snake in good condition moves smoothly through your hands with no interruption in the line of the body. That smooth line is the baseline you are checking against every week.