TRITURUS IN CAPTIVITY

THE AQUATIC PHASE

Newts in their aquatic phase make excellent captives, feeding easily and voraciously on aquatic invertebrates. Some may even learn to take commercial formula fish foods. Some species (e.g. the cristatus group, the Marbled newt, and the Alpine newt) may be persuaded to stay in an aquatic environment all year round, allowing for easier feeding, and making more conspicuous pets. A water temperature of around 20oC is ideal, although newts will tolerate much lower temperatures, and will remain active down to around 5oC. Water depth should be a minumum of 10 cm.

The aquarium substrate and planting can be chosen at the keeper's discretion, as newts are tolerant of many different environments. Likewise water quality is relatively unimportant. Although excess chlorine may be harmful, aged tap water should present no problems. A permanent set-up similar to that used for tropical fish may incorporate filters, and will need little maintenance. On the other hand, a simple, bare set-up should have regular cleaning and water changes.

A floating platform will allow newts to leave the water at will. When they spend more time on the platform than in the water, it usually signals the end of the aquatic phase.

All accommodation for newts should be kept well covered at all times, as small to medium-sized newts have no problems climbing sheer glass, and can squeeze through tiny apertures.

THE TERRESTRIAL PHASE

The terrestrial phase presents more difficulties than the aquatic phase. Adequate water must always be present, as the soft skin of newts is very prone to dessication. This is best achieved by having a moisture-retaining substrate such as potting compost, and spraying regularly with water. The substrate should never be allowed to become sodden, however. A layer of moss on top of this will provide extra moisture retention, and will allow newts to hide beneath it. Temperatures should be similar to those for the aquatic phase.

Food of an appropriate size should be supplied. Although newts may take unmoving food in their aquatic phase, this is rare when terrestrial, and either live food must be supplied, or foodstuffs must be moved to make them appear live (this is only really appropriate for the larger species, and for small numbers of animals).

COMPLEX ACCOMMODATION

More complex accommodation can be provided, seeking to mimic natural habitats. This is mainly for the benefit of the keeper, as newts will thrive in relatively artificial environments. It is possible to provide terrestrial and aquatic areas in one set-up, allowing the whole life-cycle to proceed without needing to move the animals. The more complex the set-up, however, the more maintenance it will need, and the more difficult cleaning will be.

Some enthusiasts also use outdoor enclosures to keep newts; these enclosures must be very carefully sealed to prevent escapes, and must contain all the microhabitats necessary for the animals' lifecycles, including winter retreats to allow escape from sub-zero temperatures; these are usually underground, though the minimum depth necessary will depend on the local climate. In addition, the enclosures must be covered to prevent predators from entering.

BREEDING: SEXING OF NEWTS

Triturus species are highly sexually dimorphic, and most species have unmistakeable features making sexing unequivocal for adults in breeding condition. Males will generally have crests on the body and tail, and very swollen cloacae; they are also usually smaller, and more slender than females. T. boscai is the species most likely to be problematic, as both sexes are rather similar, and the male has no crest on the body. However, males have slight dorsolateral ridges, and the females' cloacal swelling is slightly pointed.

Out of breeding condition, sexing is much more difficult,as cloacal swellings are much decreased, and crests are absent. There may, however, still be colouration differences, and some indication of the crest may still be present in male individuals (for example, T. alpestris males have a dotted line along the back, which is usually lacking in the female).

BREEDING: INITIATING BREEDING BEHAVIOUR

Some older texts recommend that newts are hibernated in order to bring them into breeding condition. This is not always necessary, but an increase in temperature coupled with extra feeding and an increase in light, after a cooler period, will help bring newts into condition. Ideal breeding temperature is usually around 15oC. If newts are taken from their terrestrial accommodation in early spring, and placed on a floating platform in an aquatic set-up, they will usually enter the water within a few days, and begin to develop their breeding colours. A method has been described (Cogalniceanu, 1989) where newts are artificially hibernated over the summer for 30-40 days, to provide a second breeding period in the autumn, but this second spawning is usually much smaller than the first.

The males will attempt to court the females with their distinctive courtship dance, taking a position in front of them, and displaying tail fanning or waving. If the females are receptive, this will lead to spermatophore deposition and fertilization.

The females will begin to lay eggs a few days later, wrapping them in plant leaves, or depositing them on any other materials present in the aquarium. This may take place over a period of several days to several weeks. As other newts may eat the eggs, it is best to remove them, or the adults, for separate rearing.

REARING NEWT LARVAE

When the larvae hatch, after a few days to a couple of weeks, they are tiny, and require feeding with equally tiny food. Infusoria, (microscopic aquatic organisms) either collected from ponds or water butts, or cultured, are an ideal first food. As they grow, they can be fed on Daphnia, whiteworm, bloodworm and Tubifex. Although adult newts may go without food for several days, the larvae should be fed daily.

Occasionally, usually through underfeeding or overcrowding, larvae will swallow air bubbles, and the buoyancy will cause them to float upside-down on the water surface. This prevents them from feeding normally, and, untreated, will lead to starvation. This can be treated by placing the larva in a petri dish or similar receptacle, and adding water, dropwise, until the larva can move freely. If the minimum amount of water is added, the depth will be small enough to stop the larva overturning. Large amounts of food animals should then be added, and the larva will usually be able to eat, the air bubbles will eventually be expelled from its anus, and it will be able to swim and feed normally again. This process can take as little as half an hour.

Eventually, after all four legs have grown, the juvenile colours will start to appear, and the gills begin to recede. At this stage, some means of escape from the water should be supplied, and the metamorphosed larvae will leave the water; terrestrial accommodation should then be provided. These young efts will then feed on aphids, whiteworm, fruitflies, and other suitably sized prey.

Efts can be maintained in the same manner as terrestrial adults, although smaller food is necessary. The efts of some species (e.g. the cristatus group, T. marmoratus, and T. alpestris) can be forced to remain in the water, and can be raised aquatically. The juvenile newts can be expected to reach maturity at between one and three years old, depending on the amount of food offered and the temperature they are maintained at. With an excess of food, and feeding throughout the winter, newts can reproduce only one year after hatching (Elebert, 1991). In nature, maturity is usually reached much later.

FOOD SOURCES

Although many newt enthusiasts are also interested in other amphibians and reptiles, the keeping of newts is in many ways more similar to fish keeping. Tropical fish suppliers will supply most of the necessary equipment and foods, such as dry foods, Daphnia, Tubifex, bloodworms and whiteworms. Livefood suppliers, as used by reptile enthusiasts, will supply suitable food for adults, such as worms, mealworms, crickets, and fruitflies.

Live foods can also be collected or bred; fruitflies are easily bred, and are a useful food for small newts in the terrestrial phase. Infusoria are easily cultured by boiling lettuce leaves, and leaving the water for a few days; there will be thousands of microscopic organisms in the water. Daphnia, bloodworms, etc., can be collected from ponds, and small invertebrates can be collected from hedgerows by shaking branches over a container. When collecting food, one should be careful not to collect from polluted areas, as collected organisms may contain toxins. If collecting from waterbodies, it may be better to avoid those containing native amphibians, as there may be parasites present which could infect captive animals.

OBTAINING SPECIMENS

There is no need for the average newt enthusiast to buy wild-caught stock, as all of the Triturus species, and many of the subspecies, are bred by private breeders, who will often have surplus eggs or young newts. Captive bred animals are more likely to be free from disease or parasites than wild-caught individuals, and purchasing captive-bred stock avoids the depletion of natural populations.

Herpetological society publications will often carry adverts from their members wishing to sell surplus animals. The large numbers of eggs and larvae produced by newts means that the cost of eggs and juveniles is relatively low. Sexing, however, is impossible at these stages, so, if breeding is intended, a small group of animals will have to be obtained to ensure that both sexes are present.

REFERENCES

Baker, J., 1988. Maintenance and Breeding of Triturus karelinii. British Herpetological Society Bulletin 25: 42-44.

Billings, D., 1985. The Care and Breeding of the Common British Reptiles and Amphibians- Part III, The Smooth Newt (Triturus vulgaris). British Herpetological Society Bulletin 11: 32-34.

Cogalniceanu, D., 1989. Reproduction twice a year of the Crested Newt in Captivity. British Herpetological Society Bulletin 30:12 -13

Elebert, E., 1991. Precocious Newts. British Herpetological Society Bulletin 35: 17-19

Mattison, C., 1992. The Care of Reptiles and Amphibians in Captivity. Blandford Press.

Waights, V., 1995. Captive maintenance of adults and juveniles of the genus Triturus during the terrestrial phase. Alytes 13(2): 77-80.