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Froggy frolics of life in our ponds

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In the century past, cave excavations in Sligo and other places uncovered bones of frogs and lemmings reckoned to be from 10,000 years back

In the century past, cave excavations in Sligo and other places uncovered bones of frogs and lemmings reckoned to be from 10,000 years back

In the century past, cave excavations in Sligo and other places uncovered bones of frogs and lemmings reckoned to be from 10,000 years back

In a laneway a frog's remains were impressed in the gravelled mud. The creature had been flattened by a passing vehicle. The imprint was shaped like the national escutcheon of the Isle of Man, with an extra limb.

The embedded legs were of an unlucky frog marking a seasonal urge after a winter buried in mud. This is breeding time and the lonely amphibian was following its instincts for a watery rendezvous with others. There is a river nearby but roads and buildings, not least a high wall, present obstacles. The frog was a reminder of what this place once looked like.

Frogs have been around for some time. There are various opinions. Some sources say pre-historic, others that the Normans brought them here as food supplies.

Donatus, a ninth-century monk, wrote (of Ireland): "No scaly snake creeps through the grass nor creaking frog annoys the lake." Giraldus Cambrensis, who wrote his share of Irish fantasies in the 12th century, held there were none here but Robert Poer, a king of Ossory, when he had his attention drawn to one, didn't like what he saw. "Very bad news," he is reported to have said, shaking his head.

In the century past, cave excavations in Sligo and other places uncovered bones of frogs and lemmings reckoned to be from 10,000 years back. One naturalist, in the 1980s, maintained there were no frogs in Dublin until a learned Fellow of Trinity College placed some spawn in a ditch in the college grounds.

The European frog is an opportunist species and can make skin colour changes from green to harmonise with background and conceal itself from predators, especially grey herons. Skin cells expand, or contract, causing the pigment to vary with the intensity of reflected light.

Irish frogs are reported to be explosive breeders, with a greater reproductive output than those in mainland Europe. They can lay more than 1,000 eggs and are quite resistant to cold emerging from hibernation to icy temperatures. Their forelegs are short with the four digits unwebbed, but the long hind legs have five webbed digits making them excellent swimmers and jumpers. Their skin, moist with the aid of glands, absorbs oxygen, as do the lungs, though air must be forced through by swallowing.

Great froggy activity may still be seen in rural locations near water, when small armies of Rana temporaria cross lanes and roads heading for breeding ponds where a mass of eggs is deposited - having been externally fertilised by the males which cling to their partners in vice-like grips. After a month, black spots will have grown into embryonic tadpoles and eventually into froglets. Children once collected spawn, to watch tadpoles grow.

The boy Seamus Heaney would fill "jampots of jellied specks to range on window sills". But a bass chorus of bull-frogs "poised like mud grenades" frightened him. He felt the "slime kings were gathered for vengeance" and if he dipped his hand the spawn "would clutch it".

But, like the Trinity Fellow, some boys collected spawn to release elsewhere before their mothers flushed away the experiments.

Sunday Independent