Pool Frogs in Uppland
Pool Frogs in Uppland
The few pool frogs that live in Sweden are all found in Uppland. They really don’t like cold water, and don’t do well in water under 16 degrees.
Why are pool frogs so rare? We believe the reason to be that pool frogs first came to Scandinavia when it was warmer, over 6000 years ago. When the average temperature sank after several thousand years, the frogs could only survive along the coast of Uppland. On the coast there are shallow ponds that warm up quite quickly in the spring, which is great for the frogs.
The pool frog’s favourite ponds eventually grew over and became swamps, which meant they had to find new ponds. Luckily for the pool frogs, the land in Uppland is rising about 6mm per year, so new ponds are being formed all the time.
In 2005, about 70 pool frogs were moved from Uppland to England. Today, this northern European pool frog is only found naturally in Sweden and Norway, but was at one point found in England as well. However, the last pool frogs in England died out in the 1990’s. Research has shown that the Uppland pool frog and the English pool frog were genetically similar, and so it was deemed to be a good match.
There are other types of pool frogs in the Baltics and Central Europe, but that’s another story.
Photo: German Oriazola
Wikipedia article on the pool frog
Video of pool frogs (Youtube)
Another video of pool frogs (Youtube)