Rights: The University of Waikato Published 3 November 2009 Download

Dr Phil Bishop, from the University of Otago, talks about his research into metabolic bone disease. This disease only affects captive frogs, and the cure involves an elaborate UV tanning booth made especially to suit our native frogs.

Points of interest

  • What happens to frogs with metabolic bone disease?
  • What factors does Phil need to monitor when he is setting up the tanning booth?


Metabolic bone disease is a disease that has been affecting a lot of reptiles and amphibians throughout the world, not just in New Zealand. The animal needs calcium in its system for its muscles and nerves to work properly, so it’s taking the calcium out of its bones and putting that into its blood to get to the nerves and muscles.

And what you find is that your animal becomes quite deformed and eventually it gets very brittle bones. The bones break just in normal walking processes, and ultraviolet light needs to activate the vitamin D that is in the skin in order to help the body take up calcium properly from its diet and then put it down into the bones. So we can give the frog enough calcium in its diet, but if it doesn’t have the necessary vitamin D or ultraviolet light, then it’s just not going to use it properly.

Most of the time we would keep our amphibians in the lab where there is no natural light at all, because in the wild, they like it dark and damp, and we are finding it quite surprising that they might need ultraviolet light.

Metabolic bone disease only occurs in captive frogs and, of course, if you’ve got frogs that are diseased then you are not going to be able to breed them. So it’s quite important this research on metabolic bone disease to ensure that we have healthy frogs that are going to produce healthy offspring in the lab.

New Zealand frogs, of course, don’t like it too hot, they don’t like it too cold, so the challenge is to hit them with a lot of UV light, which means I have to get the tanning lamp quite close to them but I mustn’t let them get too hot. So I’ve had to set up an elaborate system where I do it in a cold room, and I’ve got a fan blowing, and I’ve got moisture there, and I’m recording the temperature all the time, so that while I’m tanning them, I’m not cooking them as well.