We all are aware that we are not the species to first appear on the planet. Earlier in the Mesozoic Era, which lasted from about 252 to 66 million years ago, dinosaurs roamed the planet. It is only roughly around 300,000 years ago that Homo sapiens, from whom we trace our origin species, came into being in Africa. But who came before dinosaurs? Horseshoe crab, yes, you read that right. However, the most interesting fact about the horseshoe crab is that, unlike dinosaurs, they cohabit the planet with us even today!
Horseshoe crab originated 445 million years ago in the Late Ordovician aeon, making it one of the oldest members of the Blue Planet. There are organisms from the kingdom of plantae like Equisetum, commonly called horsetails, which originated 300 million years old and continue to exist now. Apart from these, ctenophores or comb jellies, sponges, jellyfish, velvet worms, and nautilus are some other creatures from the Animalia Kingdom that are older than Horseshoe crabs. However, it seems impossible to beat certain microbes in this competition to determine who came first. Microbes like certain bacteria, namely cyanobacteria blue-green algae, have been around for over three billion years and continue to coexist even today.
#DYK? Horseshoe crab blood is blue! In these critters, the oxygen-carrying molecule contains metal copper, which has a bluish tint. Another amazing fact about these arthropods? They're older than dinosaurs! Horseshoe crabs have survived on Earth for some 450 million years. pic.twitter.com/G8wgislN3M
— American Museum of Natural History (@AMNH) May 31, 2021Habitat of Horseshoe Crab
The organism show different habitat patterns in their entire course of life. They lay eggs on coastal beaches in late spring and summer, which, after hatching, can be found offshore on the sandy ocean floor of tidal flats. Adult horseshoe crabs live at the ocean’s deep bottom. The Atlantic Ocean and North American coastline of the United States house horseshoe crabs. They are also found along the East and Gulf coasts of the United States and Mexico. In addition to these coasts, some species of the horseshoe crab are also found in Asia along the coast of the Indian Ocean and the Pacific Ocean.
Biomedical Properties of Horseshoe Crab Blood
The blood of the creature is highly valued in the pharmaceutical industry as it is known to contain certain biomedical properties. Researches exist that demonstrates that their blue blood is characterised by a unique substance called Limulus Amebocyte Lysate (LAL). LAL is known for its ability to detect bacterial endotoxins in medical products. These are toxic components of the outer membrane of Gram-negative bacteria, and therefore, its detection leads to ensuring of safety of the products. Besides, medical experts recommend its use in checking the sterility of medical devices, pharmaceuticals, and biological products and thereby crucial in ensuring their safety for human use.
Additionally, research is underway to develop new antibiotics from the blue blood rich in antimicrobial peptides. Besides, the blue blood shows a unique clotting mechanism that scientists are trying to explore to realise the complex immune mechanism and to develop a new wound-healing treatment. In addition to that, scientists have discovered that certain proteins in the blue blood may contain anticancer properties. LAL also finds use in testing the purity and safety of under trial vaccines.
Threats that endanger the species
Most species of animals usually only last a few million years; however, the effective resilience shown by the effective immune system of the creature is seen as responsible for its unchanged condition since the Ordovician period. Despite being one of the earliest species who have managed to survive this long, horseshoe crabs are now encountering certain threats previously unknown to the species.
Overharvesting for Biomedical Purposes
The organism are harvested extensively owing to their biomedical properties. LAL is essential for detecting bacterial endotoxins in medical products and, therefore, is in high demand in the pharmaceutical industry. Due to this high industrial demand, about 500,000 horseshoe crabs are harvested each year for their blood. They are captured, bled, and released into the sea after the blood is taken from them. However, of the 30% whose blood is taken, nearly 10 to 15% of these harvested crabs die in the process.
Habitat Loss
Like any other marine species which encounter the issue of coastal land degradation, the species also experience similar environmental problems, including ocean water pollution, climate change-induced sea level rise, and ocean acidification which are detrimental to horseshoe crabs’ survival and breeding. As they utilise diverse habitats for breeding, maturing and spawning, the loss of habitat directly endangers their lives and population growth.
Predation
Predation consists of an important natural threat to their survival. A number of coastal birds, reptiles, and fish depend on the horseshoe crabs’ eggs as an important source of food. Most of the eggs, therefore, do not even reach the larval stage as they are eaten.
Use as Bait
Horseshoe crabs are harvested not just for their biomedical properties but also used as bait for fishing. This overharvesting is another cause for depleting their populations even further. The greed-driven overharvesting, along with the aforementioned factors, is responsible for endangering the lives of one of the earliest species on the Earth.
FAQ
1. When did Horseshoe Crab originate?
Horseshoe crab originated 445 million years ago in the Late Ordovician aeon, making it one of the oldest members of the Blue Planet.
2. What are the threats encountered by Horseshow crab?
Overharvesting due to its biomedical properties, use of baits, habitat loss due to coastal land development, and predation by reptiles, coastal birds and fishes are some of the threats that endanger horseshoe crabs.
3. Why is Horseshoe Crabs’ blood in high demand by the pharmaceutical industry?
The blood of horseshoe crabs is highly valued in the pharmaceutical industry as it is known to contain certain biomedical properties. Researches exist that demonstrates that their blue blood is characterised by a unique substance called Limulus Amebocyte Lysate (LAL). LAL is known for its ability to detect bacterial endotoxins in medical products.
4. Where do Horseshoe Crab live?
The Atlantic Ocean and North American coastlines of the United States house horseshoe crabs. They are also found along the East and Gulf coasts of the United States and Mexico. In addition to these coasts, some species of the horseshoe crab are also found in Asia along the coast of the Indian Ocean and the Pacific Ocean.
5. What are the other species that are older than human species yet cohabit on the Earth today?
There are organisms from the kingdom of plantae like Equisetum, commonly called horsetails, which originated 300 million years old and continue to exist now. Apart from these, ctenophores or comb jellies, sponges, jellyfish, velvet worms, and nautilus are some other creatures from the Animalia Kingdom that are older than Horseshoe crabs.
