Saturday, November 5, 2011

Drawing Animals: Horseshoe Crab

Horseshoe crabs are an ancient arthropod that is classified more closely with spiders than with crustaceans or insects. They have blue blood that is copper based rather than iron based. Though they look a bit dangerous, they are quite harmless. Their telson (tail) is simple used to right themselves when they've been flipped over. They are an important part of the diet of migrating seabirds, as migrations coordinate with mating cycles. During the mating season, they come ashore en masse,and many diet during the process. The bodies litter beaches, and are often collected by visitors. I have an incomplete shell myself (it lost its telson before I collected it) that is about six inches across. They can grow to be much bigger. Image is from Wikimedia Commons under a creative commons license.
My interpretation. Not my best.

2 comments:

  1. Nice post. I love horseshoe crabs, and have always collected the ones that died on the beach, while trying to toss back survivors. Seems to me there are many fewer on east coast beaches than when I was a kid. Unfortunately, they are "harvested" for use as bait and fertilizer in such numbers that. As a result, the survival of some shore birds (notably the red knot) is at risk, since the birds depend so heavily on horseshoe crab eggs to survive migration. I like the drawing.

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  2. That is very true. There are other factors that have been effecting numbers as well, including the construction of sea walls on their regular nesting beaches. However, the main issue remains harvesting them for bait and such.

    They're also a useful research animal, due to certain properties of their blood. One advantage of this is that they can catch them, draw blood, and throw them back.

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