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Good morning! In this episode, I would like to share with you biological data on the Atlantic horseshoe crabs.

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And it is one of the most interesting species whose development we had a chance to observe in the Gdynia Aquarium.

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I am taking you to the Northeast coast of the United States of America where the genus Limulus lives today.

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You'll meet horseshoe crabs from Maine to Florida, with peak numbers in Delaware Bay

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and in the Gulf of Mexico as far as the Yucatan Peninsula in Mexico.

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What's fascinating about horseshoe crabs is that they have existed almost unchanged for 450 million years in the ocean.

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These ancient animals have survived mass extinctions, space catastrophes, glacial periods...

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but most of all, horseshoe crabs can be fascinating by their amazing appearance.

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Its intricately constructed body, equipped with numerous legs, is made of three main parts.

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This is the head area, the body area, and the tail, which functions as a rudder underwater.

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The whole thing is covered with armor that looks like a horseshoe.

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Thus, the name. 

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Another Polish name "mieczogon" comes from the long spike - telson, which is located at the end of the carapace.

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The horseshoe crab belongs to the carnivorous Merostomata.

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The horseshoe crab diet is based on algae, polychaetes, molluscs,

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that is, everything that this animal is able to find by combing the seabed.

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The horseshoe crab has no jaws, it crushes the food it catches and then pushes the pulp into its mouth.

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The processing of such food - the further one - takes place in the stomach, which contains gravel and sand.

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In breeding, it happens that we provide horseshoe crabs with food of sinking granules.

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It is interesting that horseshoe crabs have 9 eyes, thanks to which they can see well under water even in the dark.

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It is easiest to locate the large compound eyes, which are located on either side of the head.

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They provide monochromatic vision, which means that the horseshoe crab sees the world in black and white.

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Horse crabs breed under the cover of night, during the full moon.

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Compared to other groups of invertebrates, it is an animal that reaches sexual maturity very slowly.

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The maximum recorded lifespan of horseshoe crabs is 20 years.

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About halfway through their lives, these organisms reach sexual maturity.

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The males are the first to start their migration to spawn.

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When they meet a female on their route, they stick to her body, to her carapace, with special walking legs,

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which are equipped with claws.

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In general, these legs look a bit like boxing gloves.

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Such a male can be glued to the female's carapace even for several months.

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When the females reach the beach, they lay in a hole on the beach, in such sand, up to 60,000. eggs.

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The eggs initially hatch into larvae that float in shallow layers of water.

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During puberty, we can observe phenomenon known as "moulting", i.e. getting rid of too small carapace,

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17 times.

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Females are much larger than males.

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The largest individuals, the largest specimens, are about 60 cm,

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while their weight can reach up to two kilograms.

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The life of many species depends on the number and condition of horseshoe crabs.

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They look a bit like such a living open-air museum,

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Often the horseshoe crab carapace is colonized by a large number of different species,

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we can see barnacles on it, we can see various algae or bryozoa on it.

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The horseshoe crab or its eggs are food for many groups of animals.

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for fish, for various species of sea turtles or alligators, as well as for numerous migrating birds.

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Various factors contribute to the significant decline in the population,

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here we can mention the overfishing of horseshoe crabs as bait for fish,

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a very large proportion of the population, roughly 10% of the breeding population

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dies as a result of the rough waves rolling such a horseshoe crab onto its back,

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and then he needs human help.

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Thanks to its extraordinary properties, the milky blue blood of horseshoe crabs is used in the biomedical industry.

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A liter of such blood costs 15,000 US dollars on the market.

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The procedure is such that horseshoe crabs are taken from the wild,

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1/3 of their blood volume is drained in the laboratory,

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however, after the whole procedure, pharmaceutical companies are obliged to return such an organism back to the natural environment.

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Blood volume should return to normal within a week

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and most such horseshoe crabs have a good chance of survival.

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A lasting legacy in horseshoe crab research was left by two American scientists,

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Fred Bang i Jack Levin.

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They were the first to notice that horseshoe crabs hemolymph in the presence of bacterial endotoxins,

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Produces defense aggregates visible to the naked eye.

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Soon after, they developed a test that the Food and Drug Administration

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allowed in 1977 to control the microbiological purity of drugs, infusion fluids, endoprostheses, pacemakers and vaccines.

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This test has never failed. It can be said that most people on Earth owe their lives to the horseshoe crab.

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The hope for horseshoe crabs is to start using a synthetic alternative known as recombinant factor C,

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which is equivalent to horseshoe crab hemolymph.