The ocean’s lightless zone begins some 1,000 feet below the surface, and in some places, it extends more than seven miles deep. Dark, vast and empty, it’s a difficult place to find a mate.

Deep-sea anglerfish (Ceratioidei), however, have adapted to this problem in extraordinary ways. Male anglerfish are tiny — sometimes less than one-tenth the size of the females. And when a male ...

But when it comes to relationships, some take a rather unconventional route. Pairings of deep-sea male and female anglerfishes are rather unbalanced. While the female spends her life hunting, the male ...