Newts and European Salamanders: Salamandridae

Physical characteristics: Great crested newts get their name from the large, deeply notched crest that runs along the backs of breeding males. The males also have a tail that is thick from top to bottom and is decorated with a bold white stripe. Great crested newts can be as long as 6 inches (16 centimeters). Because of an abnormality in their chromosomes (KROH-muh-sohms), or the parts of a cell that hold the DNA, 50 percent of young great crested newts die before they hatch.

Geographic range: Great crested newts live in Europe.

Habitat: Great crested newts need dense cover during their landdwelling phase and large, deep ponds for breeding.

Great crested newts live as long as sixteen years. They spend much of their lives on land, and little is known about their habits. (Photograph by Joseph T. Collins. Photo Researchers, Inc.)

Diet: Great crested newts eat small invertebrates, frog tadpoles, and the larvae of other newts.

Behavior and reproduction: Great crested newts live as long as sixteen years. They spend much of their lives on land, and little is known about their habits. When these newts are handled, glands in their skin release a bitter-smelling milky substance that humans and predators, such as water birds and hedgehogs, find highly offensive. The bright orange and black on the belly of great crested newts act as warning colors. Predators associate the color with the bad taste and do not attack the newts.

Adult great crested newts travel to ponds early in the spring. In Sweden they have been observed moving over snow and entering ponds that are still partially covered with ice. Females start the breeding season full of large eggs, but it takes males several weeks to fully develop their thick tails and their back crests. Males that come out of winter hibernation with larger fat reserves develop larger crests, and it is likely they are more attractive to females than are males with small crests.

While in breeding ponds, great crested newts are secretive by day and mate at dusk. A male takes up a position in front of a female and displays to her with rhythmic beats of his tail. The movement sends a chemical released by a large gland in the male's cloaca toward the female's snout. The male also displays his large, white-striped tail, which is bright in the dim light. If the female responds to the displays by moving toward him, the male turns and deposits a sperm bag on the bottom of the pond. The female places herself over it and picks it up with her open cloaca.

Two or three days after mating, female great crested newts begin to lay eggs, which have united with sperm inside them. This process takes many weeks. Great crested newts lay seventy to six hundred eggs, usually 150–200, one at a time, carefully wrapping each egg in the leaf of a water plant. After two to three weeks, the eggs hatch into tiny larvae, which start to feed on water animals such as water fleas. Development and metamorphosis take two to three months, and the young leave the pond in late summer and autumn looking like miniature adults. They grow larger until they are old enough to reproduce. Female newts mate several times during the breeding season, interrupting egg-laying to replenish the supply of sperm.

Great crested newts and people: Great crested newts have no known importance to people.

Conservation status: Great crested newts are not considered threatened or endangered. Their numbers are decreasing, however, as a result of changes in their habitat caused by changes in land use and farming practices. In France, however, the great crested newt is slowly expanding its range. In central France, great crested newts overlap with marbled newts, and mating between the two species is common. In some parts of France, great crested newts seem to be handling new patterns of land use better than marbled newts and are expanding into ponds previously used only by marbled newts, whose numbers are decreasing as a result. ∎