VDC test kit slider

Recent analysis determines the physiology of vitamin D synthesis in different animal species

Posted on: August 2, 2017   by  Vitamin D Council


A new study published by the journal Springer found distinct physiological differences of vitamin D synthesis in three New Zealand species: the kiwi, the tuatara and the sea lion.

Similar to humans, animals must rely on sun exposure or the diet to achieve healthy vitamin D status. A study back in 2015 analyzed the diet of a large, flightless parrot called the kakapo, and found that their main food source, rimu berries, provided these birds up to 18,000 IU per day! A recent study conducted by researchers from New Zealand aimed to discover the physiological differences between vitamin D synthesis in the skin of three very different species of animals.

The researchers included 19 kiwis, a nocturnal, flightless bird, 16 tuataras, a large sun-basking reptile and 10 sea lions. They collected blood and skin samples from all the species and measured UVB exposure in areas these animals were commonly found.

This is what the researchers discovered:

  • There was no significant relationship (p = 0.084) between UVB exposure and plasma 25(OH)D3 concentration in kiwi.
  • There was no significant relationship (p = 0.186)between UVB exposure and plasma 25(OH)D3 concentrations in the tuatara.
  • The sea lion’s’ skin produced vitamin D concentrations that were two times higher than the kiwi and tuatara (see table below).

Vitamin D concentrations after sun exposure.

SpeciesVit D3 (μg/g) at 0 hour UVBVit D3 (μg/g) after 8 hour UBV
Tuatara <0.030.084
Sea Lion0.501.60

The researchers concluded:

The results from this study show that all three species studied retained the ability to use both dietary and dermal sources of Vitamin D, although there was interspecies variation in the magnitude of dermal synthesis.”


Kale, M. et al. Interspecies differences in plasma concentrations of 25-hydroxyvitamin D3 and dermal Vitamin D synthesis of kiwi (Apteryx mantelli), tuatara (Sphenodon punctatus), and New Zealand sea lions (Phocarctos hookeri). Springer, 2017.

Test Your Vitamin D Levels at Home!

Our in-home vitamin D test kit is easy, affordable, and an accurate way to find out your Vitamin D status.

order NOW

We need your help!

We're spreading awareness on Vitamin D Deficiency
Donate NOW
Latest Articles
What is the relationship between vitamin D and childhood UTIs?

A new study suggests vitamin D may protect against UTIs among children by upregulating their own naturally occurring antimicrobial peptides.

Weekly Newsletter

Our Sponsors

December 21st is DDAY. Click here to celebrate the day with us!