What is a Gular Sac?
A Gular Sac is the throat pouch on some birds.
A Gular Sac is a featherless pouch, or bag, or sac, that is formed by the skin from the lower beak to the neck.
It is used to store fish.
Examples of birds that have a Gular Sac include the Frigate Bird, Pelican, Marabou Stork, and Hornbill.
Photographer: Martina Nicolls
Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM
Here is the list of animals with Gular pouch
https://curbearth.com/animals-with-a-throat-pouch/