| Amphibians and Reptiles | Printable Version | ||||||||||||||||||||
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Frogs and Toads
Frogs and toads are vertebrates, and together form the largest of all three orders of the class amphibia: the Anura. Frogs and toads share numerous morphological features including a broad, flat head, a short inflexible trunk and enlarged hind limbs. There are however, distinct and easily identifiable differences between the common frog and natterjack toad. Morphology The dorsal, or back, colouration of the common frog can range from brown to olive while the ventral, or front, surface tends to be white or yellow. The common frog has smooth skin through which it can breathe when submerged. Like most frogs, the common frog also has notably elongated hind limbs. The natterjack toad is dark green in colour with a characteristic yellow stripe along the dorsal surface. The skin of the natterjack toad is far rougher than that of the common frog. Locomotion As an adaptation to their different habitats, the common frog and the natterjack toad have developed different methods of movement. Although both swim and jump, the natterjack toad can also climb, walk, run and even burrow. This is in keeping with its more terrestrial mode of life. Habitat The Anura were abundant during the Carboniferous period (354 to 290m years ago) and by this time could be found in habitats as diverse as tropical swamps and coal forests. Some became mainly terrestrial while others returned to the water. As a general rule, the common frog leads a more aquatic lifestyle than that of the natterjack toad, and is often to be found in garden ponds.
The characteristic feature of a typical natterjack toad habitat is light, sandy soils often near the coast (including sand dunes). The common frog feeds on flying insects, beetles, slugs and snails while the natterjack toad eats ants, slugs, snails and woodlice. Distribution The common frog is considered to be widespread and common in Ireland. In 1997, a survey carried out by the Irish Peatland Conservation Council concluded that the common frog occurs in every county in the Republic of Ireland. The same cannot be said for the natterjack toad. The only native population is to be found in Co. Kerry (around Glenbeigh in particular) although attempts have been made to re-introduce it elsewhere, most notably in Co. Wexford. The few remaining habitats of the natterjack toad (e.g. Castlemaine Harbour, Lough Yganavan and Lough Nambrackdarrig in Co. Kerry) have now been designated as SACs (Special Areas of Conservation).
Newts Newts, along with salamanders, form a second order of amphibians: the Urodela. The common or smooth newt (Triturus vulgaris) is perhaps the least studied of the three Irish native amphibians. Morphology
The body of the smooth newt is covered in black spots. These spots are larger and more obvious in males. Habitat The smooth newt can live in a wide range of habitats including garden ponds, ditches and pools with a considerable amount of submerged vegetation. The smooth newt’s diet consists of insects, worms and slugs. Distribution The smooth newt is considered to be Britain’s most widespread amphibian but is not quite as common in Ireland.
Lizards Lizards are vertebrates and along with snakes, turtles, tortoises, crocodiles and alligators, form the class Reptilia.
Ireland has just one species of lizard – the common lizard (Lacerta vivipara). Nonetheless, a species of legless lizard or slow-worm (Anguis fragilis) is found in the Burren, Co. Clare, however, it appears to have been introduced as it was first recorded in the 1970s. Morphology The common lizard exhibits a grey-brown to dark brown dorsal surface and frequently has a dark streak running the length of the spine. The ventral surface of the male is yellow to orange while the ventral surface of the female tends to be yellowish grey. Habitat The common lizard can be found in a wide range of habitat types. In general it favours open, sunny, undisturbed and well drained habitats. Despite this affinity for warm and dry locations, it has been found that it thrives particularly well on Irish bogs. The common lizard is known to feed mostly on ants. Distribution Although the common lizard is thought to be quite widespread in Ireland, its exact distribution is not known. The Irish Wildlife Trust, with sponsorship from The Heritage Council, has endeavoured to carry out a national lizard survey, encouraging people to record their sightings of the lizard in an attempt to gain more detailed information about its distribution.
Sea Turtles Sea turtles are vertebrate reptiles and form part of the order Testudines. Perhaps the most remarkable fact about sea turtles is that they co-existed with the dinosaurs and have remained relatively unchanged for at least 100 million years. In spite of their obvious success, the IUCN Red List of threatened species 2006 listed six of the seven species of sea turtle as endangered. Only one of these species is a regular visitor to Irish shores – the Leatherback Turtle (Dermochelys coriacea). The Leatherback is considered critically endangered, especially off the Pacific Coast of the Americas.
All species of sea turtle have long front flippers for swimming and all except the Leatherback have a hard shell for protection. The Leatherback, as its name suggests, is unique in having a rubbery carapace or shell with seven longitudinal ridges. The Leatherback is the largest of all sea turtles and can reach 180cm in length and 500kg in weight. The largest specimen ever recorded was a male found entangled in a buoy rope at Harlech, North Wales in 1988. It measured 2.91m in length and weighed 916kg. Habitat Sea turtles are adapted
for life in the open ocean and most species (including the Leatherback
turtle) travel long distances between nesting areas and feeding grounds.
The primary prey of the Leatherback turtle is jellyfish. The Leatherback
in particular is a highly pelagic (open ocean) species which in general
only approaches land during the nesting season. This represents a considerable
obstacle when trying to study the animal, a problem which the Irish
Sea Leatherback Turtle Project is currently attempting to address.
Distribution The Leatherback has a worldwide distribution. It is found from tropical to sub-polar oceans but nests on tropical beaches. Important nesting areas are to be found in Surinam, French Guiana, The Caribbean, Gabon and Indonesia. With regard to Ireland, the Leatherback is most abundant on the South and West coasts. If you have sighted a turtle, please report it here. |
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