Atlantic Horseshoe Crab

Limulus polyphemus

Sheltered bay beaches — Accabonac, Napeague, Peconic shores

A living fossil older than the dinosaurs. During May and June, adults congregate along sheltered bay shorelines to spawn, timed to the highest tides around the full and new moons — their eggs feed migrating shorebirds like the Red Knot. Seatuck runs community monitoring nights and a sighting tracker.

Best time of day

Evening high tide

How to see

Walk a calm bay beach at the evening high tide around the May-June full or new moon and scan the waterline for spawning pairs. Count, don't touch; report sightings to Seatuck's Horseshoe Crab Tracker.

Operator

Seatuck Environmental Association

Cost

Free

Age

All ages

Accessibility

Beach walking

Responsible viewing

Observe from the waterline and let spawning pairs be. Never pick a crab up by its tail.

Weather / sea state

Calm bay conditions; spawning peaks on the monthly spring tides.