Smooth Newt

Appearance

Outside the breeding season, male and female Smooth Newts are hard to distinguish - both sexes are of similar size, and a similar pale brown to yellow colouration. Their main visible differences are two - the male newt has a single black line running down the centre of the spine, the females have two parallel lines either side of the centre. On closer inspection, one can clearly see that the male's cloaca is very distended, whilst the female's is nearly invisible.

During the breeding season, one can easily distinguish the sexes - the male is far darker than the female, with a tall wavy and transparent crest along the spine and tail, with dark spots covering the rest of the body, including the stomach area, which is a far more vivid pink or orange than it is in winter and autumn. The female also develops spots, but not on the stomach area, which is paler than the males, and theirs are generally smaller. The female does not develop crests. Smooth Newts have a paddle-like tail for increased swimming speeds.

The nominal subspecies, "L. v. vulgaris", is found in the United Kingdom and Ireland.

Females and non-breeding males are pale brown or olive green, often with two darker stripes on the back. Both sexes have an orange belly, although it is paler in females, which is covered in rounded black spots. They also have a pale throat with conspicuous spots. This helps to distinguish them from palmate newts that have pale unspotted throats, and with which they are often confused. When on land they have velvety skin. During the breeding season, male smooth newts develop a continuous wavy crest that runs from their head to their tail, and their spotted markings become more apparent. They are also distinguishable from females by their fringed toes.

Naming

Until around the turn of the millennium, the smooth newt was named "Triturus vulgaris" rather than "Lissotriton vulgaris", and will be found under that name in most books and many websites.. The old taxon "Triturus" was found to be a wastebasket taxon, and the smooth newt was transferred to "Lissotriton" together with the other small-bodied newts.

Status

All species of newt are protected in Europe. There are laws prohibiting the killing, destruction, and the selling of newts. While the species is by no means endangered, IUCN lists insufficient data to make an assessment for two of the subspecies.

In the UK, the Smooth Newt is protected under Schedule 5 of the Wildlife and Countryside Act with respect to sale only. It is therefore illegal to sell individuals of the species, but their destruction or capture is still permitted. They are also listed under Annex III of the Bern Convention.
The Smooth newt is the only newt native to Ireland and it is protected there under the Wildlife Acts [1976 and 2000]. It is an offence to capture or kill a newt in Ireland without a licence.

Behavior

Adult Smooth Newts emerge from hibernation on land from late February to May, and head to fresh water to breed. They favour ponds and shallow lakesides over running water. At this time both sexes of newt become more strikingly and colourfully marked, with vivid spots and orange bellies. The male also develops a wavy crest along the back and tail - the sexes are much easier to differentiate during the breeding season.

During courtship the male newt "displays" for his prospective mate by vibrating his tail in front of the female in a distinctive fashion. The male then deposits a sperm-containing capsule, known as a spermatophore, in front of his mate, who manoeuvres herself into a position whereby she can pick up the capsule with her cloaca - fertilization occurring inside the female. The female, thus fertilized, after a few days starts to lay eggs individually, usually under aquatic plant leaves at a rate of 7 to 12 eggs per day. Altogether, a total of 400 eggs may be produced over the season.

After two to three weeks, the eggs hatch to a larval form - a tadpole. For a few days the tadpoles live off the food reserves contained within their yolk sacs. After this they start to eat freshwater plankton, and later insect larvae, molluscs and similar food.

The newt tadpoles look initially like small fish fry, but later become more similar to miniature adults, but with "feathery" external gills emerging from behind the head on either side. As the tadpoles mature they develop legs, and the growth and use of their lungs is matched by a gradual shrinkage of the gills. Thus the tadpole gradually shifts from being fully aquatic to possessing a body suitable for a mostly terrestrial existence, a tadpole typically leaving the water after ten weeks.

Some tadpoles however may overwinter in the larval state, only emerging from the water the following year. Smooth Newts take around three years to become sexually mature, on average living for six years. Most adult and juvenile newts hibernate over winter in moist sheltered areas above ground, emerging in the spring.