Frogs

Frogs

(Rana temporaria)

Frogs are very common at Rannoch. You might say they are found throughout the land but we should be careful not to be complacent -

(Chytridiomycosis is an infectious disease in amphibians, caused by the chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, a nonhyphal zoosporic fungus. ... No effective measure is known for control of the disease in wild populations. - Wikipedia)

Chytridiomycosis is a worldwide problem and has a devastating effect on amphibian populations. Anyway, so far so good at Rannoch.

In spring countless thousands of frogs seek water for spawning. If a night is wet they will be on the move and hundreds cross the roads and the Schiehallion road is no exception. Sadly there are road casualties and squashed frogs are a common sight. No matter how you weave while driving slowly on the Schiehallion road to avoid running them over it is practically impossible to be one hundred percent successful.

It is amazing at what high altitudes you can find frogs and frog spawn. Each female lays hundreds of eggs but inevitably most fail to make it through to being a breeding adult. Often eggs are laid in temporary pools and so perish. There are many predators of frogs although the spawn is to some extent protected by its jelly which makes it hard for ducks, for example, to hold. The tadpoles are very vulnerable to fish, dragonfly nymphs, great diving beetles and their larvae and a host of other predators. The vulnerability of frogs and tadpoles makes them important in the ecosystem. To put it bluntly, they are food.

At Rannoch there are also many toads and newts. The toad spawn is laid in long strings whilst the frog spawn is laid in clumps. Newts lay their eggs singly and stick them to underwater vegetation.

In the breeding season male frogs croak to announce their presence to females and when they find a female they stick themselves on to her with their thumbs under the females armpits and they ride on her back for several days to ensure that they are well placed to fertilise the eggs when she lays them. The eggs need to be fertilised in water by external fertilisation (the sperm swim through the water to get to the eggs) before the jelly absorbs water and swells up. When the male is attached to the female they frogs are said to be ‘in amplexus’.

In July if you walk along the edges of Dunalastair Water you may witness the emergence of thousands upon thousands of ‘froglets’. Froglets are the tiny frogs that have come into being through the miracle of metamorphosis from tadpoles. There can be so many that it is impossible not to tread on them when walking. The early stage tadpoles feed on algae and have external gills to allow them to extract oxygen from the water. The next stage has internal gills and the legs develop while the tail is reabsorbed. The new science of quantum biology suggests that metamorphosis could not occur without quantum effects at the atomic level - Enzymes. (Biological catalysts) need quantum physics to work! - there is no need to talk of conventional miracles when we are surrounded by them and we can only exist because of them.

In winter frogs hibernate in mud under logs or in some similar moist location.

Frogs are well known to hop and in this they are distinguished from toads which crawl. Frogs have a smooth moist skin through which they can absorb oxygen in addition to using their lungs. Toads have a dryer warty skin which house distasteful substances as a deterrent to predators.

Frogs have been around for three hundred million years. Modern man has been around for no more than three hundred thousand years. We are upstarts. Let’s hope the upstart does not contribute to the loss of frogs by draining / destroying their habitats or spreading disease.

(3rd January 2020)