Animal Tales


Looking into the Light

Light Bulb

When you walk into the Aquatic & Reptile Center you’ll notice there are light bulbs inside many of the exhibits. Those lights serve a purpose, and it’s not just so you can see the animals better. The reptiles and amphibians need ultraviolet B-rays from the light bulbs, says Melissa Spreda, Aquatic & Reptile Center area supervisor. “Reptiles need UVB to start the process of vitamin D3 synthesis. This, in turn, allows the reptile (or amphibian) to process and absorb calcium, preventing metabolic bone disease.” Because this is so important, Spreda is conducting a light bulb study at the Milwaukee County Zoo to make sure the animals are getting what they need from the light bulbs.

Most people at home replace a light bulb when it’s burnt out, end of story. At the Zoo, it’s a little more involved. “A bulb can still be producing light but can be useless if not producing the proper wavelengths of UVB needed for reptiles,” says Spreda. She and a colleague set out to discover what bulbs are the most reliable and cost effective for the Zoo, and what bulbs provide the animals with the proper UV index that best replicates the wild.

Light Bulb

Spreda has set up mock exhibits behind the scenes without any animals present. She then uses both UVB and UVI meters to take measurements at various distances from the bulbs. Spreda says she has been working on this study for about two years in addition to her daily duties as a zookeeper. The results have already led to bulb changes in certain habitats inside the Aquatic & Reptile Center. Spreda was going to share her findings during a national meeting this year, but due to COVID-19 the meeting was canceled. Spreda plans to share her findings when the meeting is reschedule.

This article appeared in the July - August issue of Wild Things.