The gland can be compound tubular or compound tubuloalveolar, and the fluid it secretes (mucous, serous or lipid) varies between different groups of animals. In some animals, it acts as an accessory to the lacrimal gland, secreting fluid that eases movement of the nictitating membrane. Research has proposed that the gland has several other functions, including that of a photoprotective organ, a location of immune response, a source of thermoregulatory lipids, a source of pheromones, a site of osmoregulation, inter alia. In mammals, the gland secretes an oily substance used to preen the fur. The presence or absence of this gland is one of the cues used by palaeontologists to determine when fur evolved in the ancestors of mammals.
The Harderian gland was first described in 1694 by Swiss anatomist Johann Jacob Harder (1656–1711). He documented his findings in a paper titled Glandula nova lachrymalis una cum ductu excretorio in cervis et damis, ("A new lachrymal gland with an excretory duct in red and fallow deer", English translation).
- Payne AP (August 1994). "The harderian gland: a tercentennial review". Journal of Anatomy. 185 (1): 1–49. PMC 1166813. PMID 7559104.
- Ruben, John A.; Jones, Terry D. (2000). "Selective Factors Associated with the Origin of Fur and Feathers". American Zoologist. 40 (4): 585–96. doi:10.1668/0003-1569(2000)040[0585:SFAWTO]2.0.CO;2.
- Murube, Juan (2009). "Tear Apparatus of Animals: Do They Weep?". The Ocular Surface. 7 (3): 121–7. doi:10.1016/S1542-0124(12)70307-5. PMID 19635245.
- Hillenius WJ, Phillips DA, Rehorek SJ (2007). "'A new lachrymal gland with an excretory duct in red and fallow deer' by Johann Jacob Harder (1694): English translation and historical perspective". Annals of Anatomy. 189 (5): 423–33. doi:10.1016/j.aanat.2006.10.008. PMID 17910396.
- Harderian Gland of Wistar Rats Revised by Edmyr Rosa dos Reis, et al.