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When do horseshoe crabs spawn on sandy beaches?
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horseshoe crab
Horseshoe crab (Limulus polyphemus).
Horseshoe crabs typically spawn on sandy beaches during the spring and summer months. Specifically, in the Mid-Atlantic region, this activity occurs during the evenings of the full and new moons in May and June.12
Spawning usually takes place after sunset and often coincides with high spring tides. During these events, females crawl to the high-tide mark, where they dig small depressions in the sand to deposit their eggs in clusters of several thousand. Males then fertilize these eggs externally before the adults return to the ocean.12