Box jelly

Natural History

That square-shaped bell gives box jellies their name. This species is one of the smallest jellies in the world—adults grow to about the size of a Christmas tree light. The box jelly family includes the infamous and deadly sea wasp whose venom can kill up to 60 adult humans. But this small, harmless box jelly faces its greater danger from humans, due to habitat destruction. Without healthy, nurturing mangrove forests, it's unlikely this tiny jelly would survive.

Box jellies' eyes are more well-developed than other jellies'. Tripedalia has two complex eyes and one or more simple eyes.

They may help the jellies hunt. Their complex eyes have a lens, a cornea and a retina. In addition, the photoreceptors in box jellies' eyes are similar to those of vertebrates.

Conservation

Box jellies live in tropical mangrove swamps in Central America. Their polyps settle out on mangrove roots, and the adult jellies live sheltered in between the roots of the trees, probably avoiding predators.

Mangrove forests are among the most threatened ecosystems on our planet. They're cleared for development, agriculture, and fish and shrimp farms. Pollution and sediment from land flow into these shallow coastal habitats, threatening the diverse marine life that lives there. Without this nurturing habitat, it's unlikely this tiny jelly would survive.

Cool Facts

Box jellies' eyes are more well-developed than other jellies. Most jellies can merely sense light or dark. Tripedalia have camera-type eyes like cephalopods and vertebrates. The photoreceptors in their eyes are similar to those of vertebrates. Their complex eyes have a lens, a cornea and a retina. Tripedalia has two complex eyes and one or more simple eye(s). What do these eyes do? They may help the jellies hunt.