Some New Zealand tuatara facilities have been inadvertently harming their endangered charges by enclosing them without sufficient light, new research shows.
Without full-spectrum lighting, tuatara can suffer nutritional secondary hyperparathyroidism (NSHP), which causes bones to break and other painful conditions.
Ultraviolet (UV) light produces vitamin D, which helps the bones absorb calcium.
Research published by Massey University in the January issue of the New Zealand Veterinary Journal shows four of the 18 tuatara facilities examined in New Zealand (five overseas zoos keep tuatara) were using ineffective UV light sources and others were not supplying enough.
“The results of this study showed a significant proportion of tuatara in New Zealand are not provided with sufficient access to ultraviolet B light for the synthesis of vitamin D, which may acerbate the problems created by a poor diet,” the study said.
“Furthermore, a clear relationship was demonstrated between the availability of light and the historical risk of NSHP for animals kept indoors.”
It does not mention facilities by name or whether the problem had led to deaths.
Tuatara Recovery Group captive-management co-ordinator Barbara Blanchard, of Wellington, who helped with the study, said Christchurch’s Orana Wildlife Park had been the first to “pick up” the problem, which was then identified in a North Island facility.
All facilities had been told to ensure their tuatara had access to UV light equivalent “to what you see on a cloudy day in New Zealand”.
She said more research on the optimum UV light for tuatara was needed.