Amphibians
Marbled Newt
Triturus marmoratus · also called green marbled newt
Most European newts are some shade of brown. The marbled newt is bright green, patterned with black like polished stone, and it is one of the biggest newts on the continent. Where its range runs into the great crested newt’s, the two hybridise, and for a while people thought the hybrids were a species in their own right.
Overview
Triturus marmoratus lives in France and the Iberian Peninsula, in woodland, hedgerows, and old pasture with ponds. It reaches 13–17 cm, with a green-and-black marbled back; females and young also have a bright orange spine stripe. It spends most of the year on land and returns to still ponds to breed.
The hybrid zone
Across a band of western France, its range meets the great crested newt’s, and the two interbreed. The hybrid, once named “Blasius’ newt” and taken for a separate species, is intermediate and partly fertile. Where both live, the marbled newt favours acidic, wooded ponds and the crested newt more open ones.
Status
Least Concern but declining, from the loss and pollution of breeding ponds, farmland intensification, fish stocking, and road deaths on the breeding migration.
Marbled Newt: common questions
Is the marbled newt the same as the great crested newt?
No, they are two different species, both in the genus Triturus, but they are close enough to interbreed. The marbled newt is bright green marbled with black and is found in France and Iberia; the great crested newt is dark brown to almost black with a warty skin and an orange, black-spotted belly and ranges across much of the rest of Europe. Their distributions overlap only in a band across western France, and there the two produce hybrids. The hybrid is intermediate in colour, was historically given the name Triturus blasii and mistaken for a third species, and is partly fertile, so gene flow between the two species does occur in the contact zone.
Why does the female marbled newt have an orange stripe but the male does not?
The orange or red dorsal stripe is present in juveniles and in adult females year-round, but breeding males lose it as they develop their black-and-white banded crest for the mating season. The likely explanation is that the two sexes have different signalling needs. A male in the pond is competing for mates and displaying with his crest and tail, and a bright stripe would add little; a female, and a juvenile, spends more time on land where the broken green-black-orange pattern may serve as disruptive camouflage or as a warning that the skin is distasteful. Outside the breeding season, males regrow a fainter version of the stripe.
How can I tell a marbled newt from other newts?
Size and colour make it easy within its range. It is one of the largest newts in western Europe, noticeably bigger than a smooth or palmate newt, and the green-and-black marbled back is unlike any other European newt; the only real confusion is with the pygmy marbled newt in southern Iberia, which is smaller and duller. A breeding male has a tall, even-edged crest without the jagged break over the hips that a male great crested newt shows, and it lacks the great crested newt's rough black skin and heavily spotted orange belly.
Do marbled newts make good pets?
They are kept by specialist newt keepers and can do well, but they are a commitment and, like all European amphibians, are protected to varying degrees, so any animal must be captive-bred and legally sourced rather than taken from the wild. They need a cool, part-land, part-water setup, live invertebrate food, and a securely covered tank because they climb and escape, and they are long-lived, often more than 15 years. They also dislike being handled, so they are an animal to observe rather than interact with.