This One Species Of Animal Proves That The Moon Can Affect Biological Evolution
“The combined effects of the Moon and Sun create two tidal bulges around Earth, yielding high tides and low tides twice daily. When the Sun, Earth, and Moon all align, we get spring tides: the highest high tides possible. Tidal extremes occur during new and full Moons, with twice the magnitude of intermediate-phase neap tides. One terrestrial animal, the grunion, has uniquely adapted to take advantage of this lunar-induced phenomenon.”
There’s a species of animal out there that is absolutely reliant on the Moon for its reproductive success. The grunion, found along the pacific and baja coasts of North America, mates in an interesting fashion. The females come onto shore during high tides, where they bury the lower halves of their bodies in the sand until they stick up vertically, where they lay their eggs. The males then wrap around them, depositing sperm in an attempt to fertilize them. Now, here’s the fun thing: the eggs must remain on dry land for 10-11 days to incubate, meaning that the grunion can only do this during the highest high tides: spring tides.