When I was a child we had a medium-sized frog-pond in our overgrown garden. The house next door had a swimming pool, and every spring a handful of frogs would end up in the swimming pool and I would go round and rescue them when the pool was being prepared for use. Then one year our neighbours stayed in Spain for the spring and the swimming pool was just left. When the cover was eventually taken off in May, the whole swimming pool was swarming with the biggest tadpoles I've ever seen. Tadpoles need to eat meat before they will turn into froglets. If there are no predators (fish) to eat them then what normally happens is they run out of greenery (algae) to eat, and run out space, and they then turn cannibal - the bigger ones eat the smaller ones. But in this case they had a whole swimming pool to play in and they ran out of neither space nor food, so they just kept getting bigger. Anyway...the pool had to be cleared and I spent the day rescuing all of these monster tadpoles, which I put in our frog-pond with a few rashers of bacon. Then in the space of about three days, they all turned into froglets. Thousands of them. If I'd deliberately set up a breeding program to repopulate the whole valley with frogs, I could not have done a better job.
