Home of the Blue Bloods (video)
Annie McGehrin | April 2019
Someone wise once said that you don’t know what you have until it’s gone. I’ve never forgot where I came from, a place that is known for its chickens and farmland, home of the blue hens. Where I’m from summertime around the corner also means trips to the beach. For most of my life I have shared my home along the Delaware shores of the Atlantic Ocean with one of the oldest living creatures on Earth. Not until I moved away from Delaware did it hit me that I have been witness to years of ancient gatherings and one of the world’s greatest wildlife phenomenons.
These alien looking creatures emerge onto the shores of the Delaware Bay each spring to spawn and perpetuate their species. Although Delaware is the second smallest state, it makes up for its size with the staggering numbers of horseshoe crabs.
Growing up, I would often visit Slaughter beach at high tide as the American horseshoe crab (Limulus polyphemus) make their way onto shore, a popular destination for thousands of horseshoe crabs ready to get their matin’ on. On the drive there there’s nothing in sight except marshlands and farm fields. As I make my way onto the sandy shores, I began to realize I was outnumbered. All around me are these large creatures with helmet-shaped, barnacle-covered brown shells and a spike-shaped tail sticking out the back.
Ancient, alien-like, blue blooded, ten eyed, two feet long, eleven pounds, nineteen years to live, and ten years to sexually mature. Horseshoe crabs have ten eyes that are placed all around their bodies, yet they somehow still have considerable poor eyesight and only use it to sense light and locate mates. Because the horseshoe crab takes about a decade to sexually mature it is crucial for population densities to remain high. Despite their name, the horseshoe crab is not a crab, it is more closely related to the spider and scorpion family. They make up their own special class, Merostomata which means “legs attached to mouth”. Their underbellies expose their scorpion-like claws and in between these legs you can locate their mouth. The underbelly of a horseshoe crab looks like it’s straight out of an alien ancient world.
A big misconception about horseshoe crabs is that their intimidating tail is dangerous, but in fact it is not and it does serve a function. The horseshoe crab is harmless to humans. The tail is meant to function as a tool for digging into the sand and flipping itself over when it finds itself on its backside from a harsh wave for instance. Although, this method doesn’t work too well and it makes me wonder how they have survived all this time.
Nonetheless, these amazing creatures have been around for more years than I am able to fully get a grasp on. The horseshoe crab is often called a “living fossil” for its impressive geologic record dating back over 400 million years of survival with a practically unchanged lifestyle. Species very similar to the modern horseshoe crab were living way before dinosaurs came to the scene.
Many of the horseshoe crabs on slaughter beach crash onto the shore upside down and have a hard time levering themselves upright during high tide. In 1998, a campaign called “Just Flip ‘em” was launched across the Delmarva as an initiative to help save horseshoe crabs stranded on the beaches.
Projects like this are honorable, truly, but like many other conservation efforts this is one that may be overlooking the fact that we are driving them into extinction. Despite their seemingly immortal lineage,
horseshoe crabs are experiencing extreme decimation of their numbers in recent years. Their current conservation status has them listed as V ulnerable on the I UCN Red List of Threatened Species, meaning that this species is considered to be facing a high risk of extinction in the wild.
Horseshoe crabs are a valuable keystone species of the Atlantic coast along the U.S. and the Gulf of Mexico. They are crucial to the coastal food chain as many shore birds feast on their eggs, and larger predators like alligators, sharks, and sea turtles snack on adult horseshoe crabs. Although, the most serious predator of all for horseshoe crabs is the creatures among us, humans.
The horseshoe crab is largely harvested for its incredible live-saving blue blood. Their blood is copper-based rather than rich in iron like human blood, so it turns bright blue when exposed to air. Horseshoe crab blood is unique for more than just its color, it contains special blood cells that can be utilized in the medical industry to identify bacterial and toxic contamination. This substance is also their saving grace for how they have been able to survive for so long. Their blood allows scientists to know whether or not medical tools or vaccines are contaminated with harmful bacteria, alarming us of the presence of potentially deadly infections and preventing us from spreading it. To get your hands on a gallon of their blood, you’re going to need to fork over $60,000.
Humans are dependent on the horseshoe crab for the amazing insights that are unique to components of their blue blood. No other synthetic chemical has been produced to replicate the usefulness provided for medical industry. This serves as a reminder of the dynamic nature of life on Earth, the interconnectedness of all living things. Just as endangered shore birds such as the Red Knot rely on horseshoe crabs for one of their main food sources, we rely on them for their blood as a tool to save lives from infectious diseases.
When the blood is taken from the horseshoe crab, they draw about 30 percent of their blood and then return them into the ocean. Releasing them back into the water is grounded with good intention, though evidence shows that this has a negative impact on their ability to reproduce and survive. Will we miss them once their gone?
The commercial demand extends further, humans harvest horseshoe crabs to crush up for fertilizer and use as bait. Considering that agriculture is Delaware’s largest industry, I suspect that this threat hits close to home for me. Have we taken these creatures for granted?
Human activity from overharvesting is one explanation for population declines, but researchers suspect that climate change is also to blame. Studies show convincing correlation between population trends and historical climate change events. Given that the American horseshoe crab has a surprisingly low genetic diversity, shifts in their lifestyle is a slow process. Horseshoe crabs have successfully adapted to environmental changes for longer than many of us can comprehend, yet the question weighing down on us now is will they have time to adapt to climate change?
Annie McGehrin | April 2019
Someone wise once said that you don’t know what you have until it’s gone. I’ve never forgot where I came from, a place that is known for its chickens and farmland, home of the blue hens. Where I’m from summertime around the corner also means trips to the beach. For most of my life I have shared my home along the Delaware shores of the Atlantic Ocean with one of the oldest living creatures on Earth. Not until I moved away from Delaware did it hit me that I have been witness to years of ancient gatherings and one of the world’s greatest wildlife phenomenons.
These alien looking creatures emerge onto the shores of the Delaware Bay each spring to spawn and perpetuate their species. Although Delaware is the second smallest state, it makes up for its size with the staggering numbers of horseshoe crabs.
Growing up, I would often visit Slaughter beach at high tide as the American horseshoe crab (Limulus polyphemus) make their way onto shore, a popular destination for thousands of horseshoe crabs ready to get their matin’ on. On the drive there there’s nothing in sight except marshlands and farm fields. As I make my way onto the sandy shores, I began to realize I was outnumbered. All around me are these large creatures with helmet-shaped, barnacle-covered brown shells and a spike-shaped tail sticking out the back.
Ancient, alien-like, blue blooded, ten eyed, two feet long, eleven pounds, nineteen years to live, and ten years to sexually mature. Horseshoe crabs have ten eyes that are placed all around their bodies, yet they somehow still have considerable poor eyesight and only use it to sense light and locate mates. Because the horseshoe crab takes about a decade to sexually mature it is crucial for population densities to remain high. Despite their name, the horseshoe crab is not a crab, it is more closely related to the spider and scorpion family. They make up their own special class, Merostomata which means “legs attached to mouth”. Their underbellies expose their scorpion-like claws and in between these legs you can locate their mouth. The underbelly of a horseshoe crab looks like it’s straight out of an alien ancient world.
A big misconception about horseshoe crabs is that their intimidating tail is dangerous, but in fact it is not and it does serve a function. The horseshoe crab is harmless to humans. The tail is meant to function as a tool for digging into the sand and flipping itself over when it finds itself on its backside from a harsh wave for instance. Although, this method doesn’t work too well and it makes me wonder how they have survived all this time.
Nonetheless, these amazing creatures have been around for more years than I am able to fully get a grasp on. The horseshoe crab is often called a “living fossil” for its impressive geologic record dating back over 400 million years of survival with a practically unchanged lifestyle. Species very similar to the modern horseshoe crab were living way before dinosaurs came to the scene.
Many of the horseshoe crabs on slaughter beach crash onto the shore upside down and have a hard time levering themselves upright during high tide. In 1998, a campaign called “Just Flip ‘em” was launched across the Delmarva as an initiative to help save horseshoe crabs stranded on the beaches.
Projects like this are honorable, truly, but like many other conservation efforts this is one that may be overlooking the fact that we are driving them into extinction. Despite their seemingly immortal lineage,
horseshoe crabs are experiencing extreme decimation of their numbers in recent years. Their current conservation status has them listed as V ulnerable on the I UCN Red List of Threatened Species, meaning that this species is considered to be facing a high risk of extinction in the wild.
Horseshoe crabs are a valuable keystone species of the Atlantic coast along the U.S. and the Gulf of Mexico. They are crucial to the coastal food chain as many shore birds feast on their eggs, and larger predators like alligators, sharks, and sea turtles snack on adult horseshoe crabs. Although, the most serious predator of all for horseshoe crabs is the creatures among us, humans.
The horseshoe crab is largely harvested for its incredible live-saving blue blood. Their blood is copper-based rather than rich in iron like human blood, so it turns bright blue when exposed to air. Horseshoe crab blood is unique for more than just its color, it contains special blood cells that can be utilized in the medical industry to identify bacterial and toxic contamination. This substance is also their saving grace for how they have been able to survive for so long. Their blood allows scientists to know whether or not medical tools or vaccines are contaminated with harmful bacteria, alarming us of the presence of potentially deadly infections and preventing us from spreading it. To get your hands on a gallon of their blood, you’re going to need to fork over $60,000.
Humans are dependent on the horseshoe crab for the amazing insights that are unique to components of their blue blood. No other synthetic chemical has been produced to replicate the usefulness provided for medical industry. This serves as a reminder of the dynamic nature of life on Earth, the interconnectedness of all living things. Just as endangered shore birds such as the Red Knot rely on horseshoe crabs for one of their main food sources, we rely on them for their blood as a tool to save lives from infectious diseases.
When the blood is taken from the horseshoe crab, they draw about 30 percent of their blood and then return them into the ocean. Releasing them back into the water is grounded with good intention, though evidence shows that this has a negative impact on their ability to reproduce and survive. Will we miss them once their gone?
The commercial demand extends further, humans harvest horseshoe crabs to crush up for fertilizer and use as bait. Considering that agriculture is Delaware’s largest industry, I suspect that this threat hits close to home for me. Have we taken these creatures for granted?
Human activity from overharvesting is one explanation for population declines, but researchers suspect that climate change is also to blame. Studies show convincing correlation between population trends and historical climate change events. Given that the American horseshoe crab has a surprisingly low genetic diversity, shifts in their lifestyle is a slow process. Horseshoe crabs have successfully adapted to environmental changes for longer than many of us can comprehend, yet the question weighing down on us now is will they have time to adapt to climate change?