Identical Species at Both Poles

A marine census shows there are hundreds of identical species found at both poles. (News source.)

Tree Snail Mystery

Biologists have been wondering how a Tahitian tree snail, Partula hyalina, managed (historically) to reach two distant Polynesian islands (and not found on closer islands), and why the migrants are all white even though the snails on Tahiti are multicolored. Turns out the ancient Polynesians had a thing for white shells, so the snails were probably taken deliberately to the other islands for rearing. (News source.)