Our most well known amphibian, the Common Frog is a regular visitor to gardens across Otley. In fact our garden ponds are really important habitats for our frogs, especially when it comes to breeding time. In spring males arrive first and will perch themselves somewhere near the pond and croak to attract females, which are often significantly larger than the males. When a connection is made, the male will then often ‘piggyback' the rest of the way to the pond on a female. The frogspawn is laid in shallow, still water which is why garden ponds are perfect.
Frogspawn is fascinating, there can be up to 2000 small black eggs, each surrounded by a 1 cm jelly capsule. The raft of spawn is over 99% water but loses heat to the surrounding water very slowly, maintaining a nice warm temperature inside for the egg. Each of the many eggs are also permeable, so everyone gets their share of oxygen from the surrounding water. As the tadpoles grow they become faintly speckled with gold and brown, this is how you can tell them apart from the Common Toad tadpoles which remain all black. At about 16 weeks old, the tadpoles gradually change into froglets by first growing back legs, then front legs and finally by ‘absorbing’ their tails. This process is known as metamorphosis.
After populating your pond with tadpoles, adult frogs become our allies, if allowed to do so they can clear out those pesky slugs and snails from your garden! As adults, Common Frogs have smooth skin that varies massively in colour from grey, olive green and yellow to brown, amazingly they are able to lighten or darken their skin to camouflage with their surrounding environment and improve their chance of survival. Adult Frogs can live up to 10 years old, if they don’t get eaten first by their many predators; including grey herons, foxes, otters, birds of prey and domestic cats.
In winter frogs hibernate in pond mud, under log piles or in compost heaps. This choice of sleeping on the land or under the water is possible because the oxygen uptake through the skin is enough to sustain the frogs during hibernation. They will take advantage of milder patches of weather throughout winter, by waking up to forage. At around 3 years old the adults are ready to make more tadpoles, as soon as they wake up in early spring, they will head to a pond to breed and the cycle begins again. At this time of year it is the tiny ‘adult’ frogs you should look out for, leaving the pond for the first time to try out their land legs!