Males have royal blue wings when they are open and females are more brown. When closed, both genders have whiter blue wings with black/gray markings. They have two orange eyespots on their lower hindwings that is thought to help confuse bird predators. If the bird mistakes the eyespot for the head and pecks at it, only a small part of the wing is damaged and the butterfly can escape complete annihilation.
This small butterfly can be found in parks, gardens, meadows and anywhere else flowers are abundant. Males tend to socialize at puddles or wet mud in what are called "puddle parties".
The caterpillar of the Eastern-Tailed Blue Butterfly enjoys chewing the leaves of flowers and a variety of bean plants.