It turns out that there was a reason - but you'll have to read the book to find out! Other works in the "creatures on the sun" genre include Proof by Hal Clement and Sundiver by David Brin.
Read the original article at Solar Tadpoles Wave At Astrophysicists; they also have a very cool solar tadpole animation that demonstrates the uncanny movement that gave birth to the name "tadpoles." Thanks to Fred Kiesche at the eternal golden braid for the tip and some sf background on this story.
(This Science Fiction in the News story used with permission from Technovelgy.com - where science meets fiction.)