Often said to be the most alluring of all frog species, the blue poison frog's colouration is actually thought to function as a warning to predators that it is poisonous. Its limbs are royal blue, fading into an attractive sky blue background, peppered with both large and small black spots. The underside is similarly patterned, and may also sport a darker stripe down the centre (4). This species has a hunched body posture and large, black eyes. Females are plumper than males but may be more accurately distinguished by their toes. The blue poison frog has four toes on each foot, with enlarged suction cup tips to each toe. In the female these tips are round whereas in males they are heart-shaped (2).