Hello,
The following observations are drawn from my notebooks...the first involves animals in my own collection, the second occurred during my tenure at the Bronx Zoo's Dept. of Herpetology. Any feedback would be most appreciated, thank you.

Many years ago I kept 2 African clawed frogs (Xenopus laevis) that would "bask" on a rock which protruded above the water, directly under an incandescent bulb. This only occurred in winter, when the water temperature in their tank averaged 66 F, so I thought they might be seeking warmth. However, others I’ve kept at that temperature have not left the water, despite being provided with a basking light as well.

The second observation involves a female clawed frog that laid eggs in absence of a male. That in itself is unusual. Odder still, however, was the fact that a male placed in the tank with the eggs (and without the female) on the following day fertilized the eggs. He was in breeding condition, as (“nuptial pads” along his forearms), and perhaps was responding to pheromones in the water, but still should have (according to me, not him, it seems!) required a female to stimulate sperm release. I have spoken with a number of herpetologists about this, and none can recall a similar incident.

These observations date back decades, so I am most anxious for any input!

I have posted a number of articles dealing with the natural history and care of amphibians, reptiles, fishes, invertebrates and birds at:
http://blogs.thatpetplace.com/thatreptileblog
http://blogs.thatpetplace.com/thatavianblog
http://blogs.thatpetplace.com/thatfishblog
Thanks, Frank.