According to one study grey tree frogs can go without food for up to six weeks without any ill effects (1). This is an incredible feat considering that these frogs usually only live for around two to three years in the wild (2).
The reason why grey tree frogs can survive for so long without food is due to their ability to enter into a state of hibernation. When the weather starts to get cold and food becomes scarce grey tree frogs will burrow into the ground and enter into a deep sleep (3). This sleep can last for several months during which time the frog will not eat or drink.
Of course during this time the frog will be losing a lot of weight. But it is able to survive on its stored body fat and does not need to eat anything. Once the weather starts to warm up again the frog will come out of hibernation and start to look for food (4).
So how long can a grey tree frog go without food? It is really amazing how these creatures can survive for so long without eating anything!
Reference:
1. https://www.researchgate.net/publication/228607606_How_long_can_a_grey_tree_frog_Hyla_versicolor_go_without_food
2. https://animaldiversity.org/accounts/Hyla_versicolor/
3. https://www.iucnredlist.org/species/55864/106875405
4. https://www.thoughtco.com/facts-about-the-grey-tree-frog-1093740
