Great Crested Newt
Tagged: animal, animals, bird, fish, invertebrateTriturus cristatus
Although the great crested newt is widely distributed across Europe, the species has declined over much of its range. Changes in land use and agricultural practices over the last 50 years have destroyed much of its pond and woodland habitat. The great crested newt of northwestern Europe-along with other European newts of the genus Triturus-gets its name from the large, deeply notched crest that runs along the back of the breeding male. The European newts are unique among tailed amphibians: During the breeding season the males develop elaborate decorations that serve to attract and stimulate females during courtship. Although great crested newts spend much of their lives on land, breeding takes place in water. Adults migrate to ponds in early spring. Females start the breeding season already full of large, yolk-filled eggs. It takes the males several weeks to fully develop their deep tail and crest, features that play an important part in the mating process. Males that emerge from their winter hibernation with larger fat reserves develop larger crests, and it is likely that they are more attractive to females. Mating usually occurs at dusk. The male takes up a position in front of the female and displays to her with rhythmic beats of his tail. If the female responds by moving toward him, the male deposits a package of sperm, called a spermatophore, on the floor of the pond. The female then moves over it and picks it up with her open cloaca (cavity into which the genital ducts open). Two or three days after mating the female begins to lay her eggs, a process that takes many weeks. Great crested newts usually produce between 150 and 200 eggs, each of which is laid individually and carefully wrapped in the leaf of a water plant. After two to three weeks the eggs hatch into tiny larvae, which, once they have used up their reserves of yolk, start to feed on tiny aquatic animals, such as water fleas. Larval development takes two to three months, and the young emerge from their pond as miniature adults in late summer and fall. Females mate several times during the breeding season, interrupting egg¬laying to replenish their supplies of sperm.
Risk Factors
Together with its close relative, the marbled newt, the great crested newt has a remarkable abnormality of its chromosomes. As a result, 50 percent of its young die as early embryos. This is one reason, perhaps, why crested newts have declined more rapidly than other European newt species. Predation is not a significant problem for great crested newts. When handled, glands in their skin produce a bitter, milky secretion that humans and potential predators, such as water birds and hedgehogs, find lip distasteful. In addition, the bright orange and black pattern on the belly appears to warn off predators. However, crested newts are at risk from habitat alteration and destruction. The main problem has been changes in land use since World War II. Woodlands have been cleared, hedges destroyed, and land drained to make way for crops and livestock. Ponds, which were a common feature of the European landscape, have been filled in. In some parts of Britain, for example, 90 percent of farm ponds have disappeared in the last 50 years. Another threat to crested and other newt species comes from fish that eat newt larvae. The eggs and larvae of crested newts are also sensitive to a variety of pollutants, such as herbicides and pesticides. In the southern parts of its range the crested newt is found in a number of forms that differ from the northern form in having longer bodies, shorter legs, and a different shape of crest on the male. Such forms are now recognized as three distinct species: the Italian crested newt, the Danube newt, and the southern crested newt. All are threatened by habitat loss and protected, to varying degrees, by national and European laws. At the southwestern edge of its distribution, however, the crested newt is expanding its range. In some parts of France it appears to be adapting to new patterns of land use and is even spreading into ponds previously used only by marbled newts.
Great crested newt (warty newt)
Triturus cristatus
- Family: Salamandridae
- World population: Unknown
- Distribution: Northwestern Europe
- Habitat: Woodland, scrub, and hedgerows close to ponds, lakes, or ditches
- Size: Length, male 3.9-5.5 in (10- 14 cm); female 3.9-6.3 in ( 10-16 cm)
- Form: Dark gray or brown newt with large black spots on upperside; bright orange underside with black spots. In breeding season male (only) has large, dorsal crest and deep tail with white stripe
- Diet: Small invertebrates
- Breeding: Mates in spring and early summer. Between 70 and 600 (usually 150-200) eggs laid; larvae hatch after 2 week gestation; young develop over 2-3 months. Life span up to 16 years
- Related endangered species: Danube newt (Tristurus dobrogicus)
In the breeding season the male great crested newt develops a distinctive crest and tail, which he displays during courtship. A, tail has a conipicuous white stripe that shows up clearly in the dim light of dusk-when mating occurs.
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