Epidexipteryx was one of the smallest non-avian dinosaurs to ever exist, measuring in at only 25 centimetres in length, discounting its tail feathers. This dinosaur was one of the first to have ornamental feathers. These feathers were most likely used for display in mating rituals or intimidation. Epidexipteryx also possessed an elongated third finger which was probably used to dig into tree bark, suggesting that it may have been primarily arboreal, only coming to the ground to forage for food if the trees lacked it. Epidexipteryx was an insectivore, preying on insects and grubs.
An Epidexipteryx was seen on a log searching for food. However, whilst looking for food, a juvenile Sinraptor stalked it. The Epidexipteryx noticed it and the Sinraptor quickly approached. The Epidexipteryx found refuge inside the log. Even though the Sinraptor couldn't reach the Epidexipteryx, it stayed adamant. As it appeared that the Sinraptor gave up, the Epidexipteryx turned to exit the log but it was ambushed by the Sinraptor. The small dinosaur ran out the opposite end and the Sinraptor followed in hot pursuit. However, the Epidexipteryx escaped by climbing up a tree.
As the Sinraptor left, the Epidexipteryx began digging into the tree's bark in search of food. Further up the tree, it found a hole contains a beetle grub. As the Epidexipteryx caught the grub, another larger Epidexipteryx challenged it for the food and dominated. The pair then began mounting an aggressive display towards each other using their ornamental tail feathers. However, the smaller Epidexipteryx backed down.
As the smaller individual found another beetle grub in the tree, it accidentally dropped it. The larger Epidexipteryx climbed down the tree to snatch it. As it ate the grub, the Sinraptor reappeared and swiftly attacked and killed it. The smaller Epidexipteryx watched as the other was taken away.
- Epidexipteryx is the smallest non-avian dinosaur in the series, and potentially, the smallest non-avian dinosaur that has ever been named (by now).
- Epidexipteryx appears to most likely have wings for gliding, as shown in dinosaurs in its family like Yi qi and Amboptreyx.