I understand that toads are capable of altering the tone of their skin to suit their surroundings. Can anyone tell me how quickly they are able to do this and whether there is a limit to the number of times they can change?
This seems to be a combination of fact and myth.
Our common toad Bufo bufo does seem to change colour with age (and possibly with the seasons), but I don't think there is evidence that this is anything like the chameleon's ability, or particularly "controlled" by the toad. It may be more a response to the climate and body condition. By all accounts it is a slow process.
There is some natural colour variation, and this may act selectively in certain habitats by making the toads more or less conspicuous to predators.