HORSESHOE CRABS- Mating

For about eight months out of the year, Horseshoe crabs stay submerged in deep Atlantic waters. Well, this month, they’ll be making an appearance on beaches along the east coast of the United States, giving us humans a chance to witness their annual mating ritual. I’m Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

Listen carefully and beneath the cries of seagulls, you can hear the sounds of a Horseshoe crab’s five pairs of legs.

John Tanacredi is Chief of Natural Resources at Gateway National Recreation Area in New York.

“Between middle of May and up until early August, these animals come out of the ocean and come onto the shorelines to mate along the coast.”

Each female Horseshoe crab is about 25% larger than her mate. It’s a size advantage she’ll need as she deposits clusters of eggs in the sand, pulling the male behind her as she goes.

“The males are very aggressive and and they move up onto the back of the female, attach onto the female with their very specially adapted front claws which have these grooves as you can see there. They’re kind of swollen little ends here that attach right onto the side of the female and release sperm over the eggs and the eggs were deposited along the shore. We don’t really know what determines what male will actually be mating with a female. But once a male attaches to a female they’re pretty well attached. It’s hard and difficult to remove the male.”

In some cases, males will remain attached to females for up to two weeks. It’s one way of ensuring that the eggs are indeed fertilized.

Pulse of the Planet is presented by the American Museum of Natural History. Additional funding for this series has been provided by the National Science Foundation. I’m Jim Metzner.

HORSESHOE CRABS- Mating

When a male horseshoe crab finds his mate, he holds on tight and doesn't let go.
Air Date:06/01/1999
Scientist:
Transcript:

For about eight months out of the year, Horseshoe crabs stay submerged in deep Atlantic waters. Well, this month, they'll be making an appearance on beaches along the east coast of the United States, giving us humans a chance to witness their annual mating ritual. I'm Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

Listen carefully and beneath the cries of seagulls, you can hear the sounds of a Horseshoe crab's five pairs of legs.

John Tanacredi is Chief of Natural Resources at Gateway National Recreation Area in New York.

"Between middle of May and up until early August, these animals come out of the ocean and come onto the shorelines to mate along the coast."

Each female Horseshoe crab is about 25% larger than her mate. It's a size advantage she'll need as she deposits clusters of eggs in the sand, pulling the male behind her as she goes.

"The males are very aggressive and and they move up onto the back of the female, attach onto the female with their very specially adapted front claws which have these grooves as you can see there. They're kind of swollen little ends here that attach right onto the side of the female and release sperm over the eggs and the eggs were deposited along the shore. We don't really know what determines what male will actually be mating with a female. But once a male attaches to a female they're pretty well attached. It's hard and difficult to remove the male."

In some cases, males will remain attached to females for up to two weeks. It's one way of ensuring that the eggs are indeed fertilized.

Pulse of the Planet is presented by the American Museum of Natural History. Additional funding for this series has been provided by the National Science Foundation. I'm Jim Metzner.