Slow frogs!

[Pyrausta]

Most of the tadpoles in my pond metamorphose and leave really fast, but there are always a few left. There are still some now and there are usually some into the autumn. Anyone any idea why? I have some guesses. You would expect most to mature fast, to get the chance to feed up in the summmer and be strong enough to survive the winter, so:
1- Dimorphism. Some frogs in transitory ponds have fast and slow larvae. The fast ones eat the slow ones!
2 - Spread. If some disaster takes all the early ones, there are still some left.
3 - Parasitism. I'm sure ancient beasts like frogs must have parasites. In some creatures, parasites delay or prevent maturation.
4 - Chemical? I gather some types of axlotle require iodine to become mature adults. Could the trace elements in the pond be to blame?
5 - Food. Lack of food might delay maturation, but the pond is full of all kinds of invertebrates.
6 - ?

Thanks - Jonathan

[Dan Salter]

Im not sure if you mean there are tadpoles left or mature frogs that havent left the pond?

[Pyrausta]

Originally Posted by Dan Salter

Im not sure if you mean there are tadpoles left or mature frogs that havent left the pond?

I mean there are tadpoles that have not metamorphosed. There are frogs hanging around all year.

[Dan Salter]

oh ok...im afraid i cant give you the answer i just wanted to clarify so others can help you .

[Digifrog]

Originally Posted by Pyrausta

I mean there are tadpoles that have not metamorphosed. There are frogs hanging around all year.

hi There...

It could be that they are Neotenous tadpoles. In rare cases you may encounter 'neotenous tadpoles'. These are taddies that are unable to metamorphose and often continue to grow. In some cases up to 4 inches long. Please let Froglife know if you find tadpoles this length in your pond. It could be that they might be an exotic species.
Please also download the PDF information sheets @ www.froglife.org. The information there will be able to assist you in common problems, and more serious threats like chytridiomycosos and ranavirus.

[Pyrausta]

Originally Posted by Digifrog

hi There...

It could be that they are Neotenous tadpoles. In rare cases you may encounter 'neotenous tadpoles'. These are taddies that are unable to metamorphose and often continue to grow. In some cases up to 4 inches long. Please let Froglife know if you find tadpoles this length in your pond. It could be that they might be an exotic species.
Please also download the PDF information sheets @ www.froglife.org. The information there will be able to assist you in common problems, and more serious threats like chytridiomycosos and ranavirus.

No, they are normal size tadpoles, some rather small. I have the froglife stuff and have asked the same on RAUK. No useful responses.

[Gill Catton]

I suspect it may be a combination of factors as you have described, pehaps there is a climate aspect too, being cold blooded animals perhaps those that hang around the bottom of the pond develop more slowly because it's cooler there - but this species has perhaps evolved to have this split for the reasons you highlight?

[Pyrausta]

This year most appear to have gone, except some rather inactive small specimens. I'd still be very interested to learn something about frog parasites. Is there a good book? They must have nematodes, but probably have other infestations. Parasites are always horrible, but also fascinating.

Jonathan

[stanleydog]

I too have plenty of tadpoles with no signs of legs, through to fully developed froglets.The spawn was layed in mid February.My pond is about 3 years old,6ft by 3ft with plenty of native plants and full of invertebrates.I think I`ve read somewhere that tadpoles can secrete a chemical to inhibit the growth of others, thus providing a food source.Also, a lack of protein can stop metamorphosis though my pond seems full of natural food/drowned snails!Maybe it`s down to overcrowding?
Jason.

[Dogghound]

Tadpole growth is an interest subject, there are lots of reasons, growth varys from pond to pond, from year to year, Sometimes it can take till almost autumn. How long have you had your taddies? another interesting fact is that tadpoles grow faster when theres more predators in the pond. It could be Neotenous tadpoles although its not common, i did find a moorland pool full of Neotenous palmate newts last winter.
Food is important and tadpoles would probrably try and eat eachother if food was in short supply something to look for. The fact its been a cool wet summer will not help the speed of tadpole growth.

[Kayleigh]

We still have lots of toadpoles in the pond. We also have a barrel that had frog spawn in. Where some of the tadpoles still hadn't changed. Past tence just noticed a newt in the barrel.

[Dogghound]

Originally Posted by Kayleigh

We still have lots of toadpoles in the pond. We also have a barrel that had frog spawn in. Where some of the tadpoles still hadn't changed. Past tence just noticed a newt in the barrel.

A big fat newt i wonder how common this is this year with tadpoles? could possibly due to cooler temp