Supraorbital gland
The Supraorbital Gland is a type of lateral nasal salt gland found in some species of marine birds, specifically
penguins, which converts saltwater to fresh water. The word supraorbital refers to the area just above the eye, or as sometimes referred to, the
orbit of the eye. It functions very similarly of the kidney.
Living in saltwater environments is a large problem for penguins, as
saltwater can be detrimental to their health. Although penguins do not directly drink water, it is taken in when they engulf their
prey. As a result, saltwater enters their system and must be effectively
excreted. To do so, the supraorbital gland, has evolved in the penguin. The gland is located just above the eyes, and surrounds a
capillary in the head, flowing in the opposite direction so as to constantly strain out saltwater that passes through. The gland secretes
brine as a byproduct, with roughly five times as much salt as would normally be found in the water flowing through the animal's body, proving the supraorbital gland very efficient. The brine is then excreted from the penguin through its
bill. Often the fluid drips out, giving the appearance of a runny nose, however it may also be
sneezed out. Being in fresh water, most often due to captivity, the supraorbital gland will simply lie dormant, as it has no other purpose. This does not negatively affect the health of the penguin.
*http://numbat.murdoch.edu.au/Anatomy/avian/avian5.html
*http://www.zoo.org/educate/fact_sheets/penguin/penguin.htm
