Toad

Bufo bufo

Common Toad

Creative Commons - credit Charles J Sharp

When thinking of toads it is hard not to let the mind drift to ‘Wind in the Willows’ and ‘Toad of Toad Hall’ pompously driving his expensive car.

Creative Commons - credit Paul Bransom

Wrenching the attention away however, we can focus on a very successful amphibian which is common at Rannoch. The adult is covered in so called warts which are not warts at all, of course, but raised areas in the skin which secrete toxins. The toxins are very effective at protecting the toad from the likes of foxes, badgers and dogs. As well as being toxic the secretions are also distasteful and predators soon drop the toad.

Toads don’t hop with the athletic vigour of frogs but they can manage a rather feeble hop otherwise they tend to crawl. When you taste horrible you can afford to dawdle.

Like frogs toads undergo metamorphosis, from tiny tadpoles with external gills to larger tadpoles with internal gills to toadlets equipped with legs to adult toads. The adults get most of their oxygen through lungs but can take in some through the skin. They spend more time away from water than frogs and lose water less rapidly though their somewhat thicker skin.

The cutting edge science of quantum biology is unearthing the fact that the metamorphosis of amphibians would not occur without ‘quantum effects’ - the enzymes that govern metamorphosis could not work fast enough without the quantum effects at atomic level. There is much yet to be learned about how life really works.

Late stage toad tadpole.

Creative Commons - credit B Kimmel

As with frogs spring is a time for reproduction for the toad and in Rannoch huge numbers emerge from hibernation to seek water for spawning. The males croak to attract females and then grab them in a ‘bear hug’ to make sure that they are present when the eggs are laid so that they can fertilise them.

Creative Commons - toads in amplexus - credit quarti

In getting to the spawning grounds many are killed on the roads and the approach roads to Rannoch can be littered with squashed corpses. If a 1000 or more toads cross a road on their migration to spawning grounds a ‘toad crossing‘ can be declared.

Creative Commons - credit Dicklebers

For the females the danger may not be over when they get to the water. They may be swamped by over-eager males who all clamp on to form what is termed a toad ball. As a result the female may be drowned. It is not always an advantage to be attractive.

The spawn comes as triple strands which are wrapped around water weed. The strands may be up to 7 metres long and contain 4000 eggs. The jelly around each egg swells when it is in water and this is a protection against being eaten.

Toads feed on invertebrates but can take surprisingly large prey such as slow worms (possible at Rannoch), small grass snakes (not at Rannoch) and harvest mice (not at Rannoch).

As well as the Common toad (Bufo bufo) there are also Natterjack toads (Epidalea calamita) in Britain but they have a very restricted range and are not found at Rannoch.