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Horseshoe Crab
Horseshoe crabs are not true crabs (lack mandible) and are more closely related to spiders.
Horseshoe Crab
They have been around for 450 million years and are virtually unchanged. They can live 20+years.
Horseshoe Crab
They are in the class called Merostomata, meaning legs attached to mouth. Food is pushed toward the mouth on its underside. Book gills are used for breathing.
Horseshoe Crab - Male
Claws look like scissors but on a male, the front one looks like a hook. Those of the females are all scissor like.
Horseshoe Crab
They have 10 eyes...2 on each side (total of 4), 3 in the front, tail tells day and night, and 2 eyes are on the underside beside the mouth.
Horseshoe Crabs
Their blue blood controls bacteria. Scientists harvest some of their blood and make the compound LAL which is used to test injectable drugs, surgical tools, hip and knee replacements etc. because it reacts to bacteria, helping to ensure the safety of such items.
Horseshoe Crab - male
The front of the shell of a male is raised since it has to fit over the female's shell when mating.
Horseshoe Crab
The female is always larger than the male because they molt an extra time. The female shell is flat across the front.
Horseshoe crab
Another way to identify a female is to look for a scarred area on the shell from mating.
Horseshoe Crab
The tail (telson) serves 3 purposes: it is an "eye" that tells day from night, it helps steer, and if tipped over.....
Horseshoe crab
.....the telson is placed in the sand and used to help flip over.
Horseshoe crab
Never pick one up by the tail. On an adult, like this one, if the tail is broken it can not steer well and can not flip itself.
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