The Hawaiian happy face spider (Theridion grallator) is endemic to the Hawaiian archipelago.
Small (< 5 mm) and fairly inconspicuous despite their unique coloration, happy face spiders live
on the underside of leaves on the islands of Oʻahu, Molokaʻi, Maui, and Hawaiʻi. The spiders are
polymorphic, showing individual variation in the pattern and color of their abdomen, from plain yellow to patterns resembling smiling and frowning faces. Interestingly, female happy face
spiders provide maternal care to their offspring by feeding and guarding them against predators. Do you find these expressive creatures more charismatic or creepy?

Sketch and fact contributed by Jessica Schaefer

Source: Gillespie, R.G., 1990. Costs and benefits of brood care in the Hawaiian happy face
spider Theridion grallator (Araneae, Theridiidae). American Midland Naturalist, 123,
pp.236–243.