Amphibians
Alpine Newt
Ichthyosaura alpestris · also called alpine newt
The alpine newt is a small, plain-backed European newt hiding a shock of colour underneath — a completely unmarked orange belly. In spring the males transform into something even more striking: steel-blue, with a speckled black-and-white flank stripe and a neat pale crest.
Overview
Alpine newts live across central and southern Europe, from lowland ponds up to about 2,500 metres in the Alps and other ranges — one of the more cold-tolerant European newts. They breed in still water in spring and spend the rest of the year on land in damp woodland and meadow, sheltering under logs and stones. They are carnivores, taking invertebrates, tadpoles, and the eggs and larvae of other newts, including their own kind.
Identification
- Belly: strong, even orange with no markings — the key feature
- Back: plain dark grey to blue-black
- Breeding male (in water): smooth steel-blue back, a black-and-white speckled band low on the flanks, and a short, straight, pale crest
The bright belly is a warning of the newt’s toxic skin, displayed in the “unken reflex.”
Newts that never grow up
In cold, fishless mountain lakes, some alpine newts are paedomorphic — they keep their larval gills, stay fully aquatic for life, and breed without metamorphosing, the same strategy as the axolotl. It pays off where the water is stable and the land is harsh.
Introduced trouble
Native to Europe, the alpine newt has been introduced to Britain, the Netherlands, and New Zealand. In Britain it preys on and competes with native amphibians and has been found carrying the chytrid fungus, so releasing it is illegal.
Status
The alpine newt is Least Concern, common across most of its range, though declining locally with pond loss.
Alpine Newt: common questions
How do you identify an alpine newt?
The two reliable features are the belly and, in spring, the male. The belly is a strong, even orange to orange-red with no spots or blotches at all — most other European newts have a patterned or paler belly — and the throat is usually the same colour. The back is plain dark grey, blue-grey, or nearly black, without the bold markings of a great crested newt or the stripe of a smooth newt. In the breeding season a male in water is unmistakable — a smooth, slaty-blue back, a black-and-white speckled band along the lower flank, and a low, straight, pale crest from the head to the tail, quite different from the tall, ragged crest of a male great crested newt.
What is a "paedomorphic" alpine newt?
It is an alpine newt that never completes metamorphosis. Normally the larva hatches with feathery external gills, grows through the summer, then transforms — absorbing the gills, switching to lungs, and moving onto land as a juvenile. In some populations, particularly in cold, high-altitude lakes and pools that lack fish, a proportion of individuals skip this. They keep their gills, stay in the water permanently, grow to adult size, and breed as gilled aquatic adults. This "staying larval" strategy (also seen in the axolotl and some tiger salamanders) can pay off where the water is stable and cool and the surrounding land is harsh, so the cost of leaving the water outweighs the benefit.
Is the alpine newt a problem where it has been introduced?
In parts of Britain, yes. Alpine newts have been released or escaped from garden ponds and now breed at scattered sites across the UK. They are voracious predators of other amphibians' eggs and larvae, they compete with the three native newt species, and — a more serious concern — introduced alpine newt populations in Britain have been found carrying the amphibian chytrid fungus, which they tolerate but which can devastate more susceptible native species. For this reason, releasing alpine newts (or any non-native amphibian) into the wild is illegal in Britain and discouraged elsewhere.
Why is its belly so brightly coloured?
The bright, unmarked orange belly is a warning signal (aposematism). Like other newts, the alpine newt has skin glands that secrete toxins — including tetrodotoxin-related compounds — that make it unpalatable and potentially harmful to predators. When threatened on land, it can perform the "unken reflex," bending its head and tail upward to display the vivid underside, telling a bird or a snake that it is not worth eating. The colour is at its most intense in the breeding season and in males, when the whole animal is putting on a display.