Frog-marching and ‘Peter Pan’ tadpoles – 8th March

I had a run-in with a ‘knot’ of toads at the weekend. Like me, they were heading down my parents’ tarmac drive – I was heading to the house to watch some Saturday night TV and they were heading to the pond to bonk and spawn eggs. 

It was lucky Dad had his headtorch on – we spotted six toads one of whom had hitched a piggyback ride on the other (males generally ride on females). It was drizzly, dark and Mr Puss was inside (not a fan of wet weather and a big fan of Saturday night TV) so they picked the perfect moment to get on the move. 

Unlike Mr Toad of Toad Hall, real toads (and frogs) are quite modest in their requirements and spend winter months slumbering in compost heaps, log piles or hedges. If the weather is mild they might do a bit of foraging for slugs, snails and insects. They properly wake up when it gets to 7 or 8C and then migrate back to the pond or puddle where they were born. 

During cold nights, male frogs literally burrow down into the mud at the bottom of the pond. They enter a state of semi-hibernation and breathe through their skin. Some of them spend the whole winter down there! Female frogs, baby frogs and all toads hibernate on land. 

After months of fooling around as tadpoles, the new froglets and toadlets leave the pond sometime between June and September. They may not return until they’re ready to breed themselves, two or three years later.

However, some tadpoles remain in a state of childhood for their whole lives. These ‘Peter Pan’ tadpoles lack a gene which produces the growth hormone thyroxine. They can survive for several years and reports from Suffolk suggest they can grow up to 12cm in length and have heads the size of 2p coins (hmmm). I am going to Suffolk this weekend and will be looking into their ponds. 

However, not all winter tadpoles will remain in a state of childhood. If the water is too cold or they are short of food, tadpoles ‘overwinter’ before they complete their development. This is a clever strategy as they can leave the water in early spring before other tadpoles have developed. They are also better at surviving in low-oxygen conditions and can respire across their skin more effectively than frogs and toads. 


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