Have you seen this? - Xenopus basking; fertilizing without amplexus?

[findiviglio]

I've had groups of juvenile xenopus attempt to crawl up the corners of their tubs in the winter before, but I use no light. Escaping the cold would be a good explaination because the rest of the year the same age frogs never did this, only when the temps got down to the upper 50's they'd start.

Thanks very much, Jake!...that's the closest I've heard to a similar observation in the 15 years I've had this in mind. They will leave the water when stressed in other ways - drought, poison, etc., so it does follow. I read of a population that lives in the subterranean water supply system of a castle in England (who thought of that introduction!?)..I believe it is in Biology of Xenopus. The water stays cool - 50's I believe...reproduction seems not to occur but marked frogs are 16 or so years of age...need to follow up on that study, thanks for the prompt.

[tylototriton]

So I did some snooping on the thermoregulation observation. I was looking through Kentwood Wells " The Ecology and Behavior of Amphibians," and he has a small section on thermoregulation in aquatic amphibians. The gist of what he says is that it is documented, but most of the studies have been done with larvae and a few with caudates, none (as of the publication of this book) with adult aquatic frogs. The book was published in 2007 so I think its pretty up to date. Its certainly a topic which deserves further study.

In regards to the fertilization after the fact I have found very little. There were a couple papers that mentioned the effects of delayed fertilization, but none that documented its occurrences or causes. This too is a very intriguing topic.

Alex

[findiviglio]

Thanks for your time and trouble, Alex. Barron's will put out a second edition of Newts and Salamanders this spring...I'm not sure of format yet, but if possible I'll include add something re thermoregulation. Best, Frank.