Metamorphosis is a process that has inspired various works in different fields of the Arts. Franz Kafka wrote a short story, Salvador Dali painted his Metamorphosis of Narcissus in 1937 and Hilary Duff sung about it in 2003. What's happening in my pond is much lower key but just as impressive.
This year the cold weather didn't arrive at the critical time in the development of the frog spawn and consequently the tadpoles arrived in good numbers. They are now getting larger, although as far as I can see none are developing legs yet.
As tadpoles develop they quickly loose their external gills and develop internal gills that are used to extract oxygen from the water. They graze on algae and, depending on the temperature of the water they slowly change. At the early stages they form groups, like small fish, and can appear in masses at the edges of ponds in good years. They become omnivorous and start to develop lungs after a few weeks.