Sea hedgehogs are part of the Echinodea class. Namely and equally are marine echinoderms with spherical body covered with spikes.
They can be found in all seas and oceans. They are related to the sea stars, and the sea cucumbers.
Sea Hedgehog’s Food
Sea hedgehog feeds mainly on algae, but can also feed on a wide range of invertebrates such as mussels, sponges, crinoids, etc.
Sea hedgehog is the favorite pot of seafood.
If left unattended by biologists, they can cause serious damage.
Sea Hedgehog’s Aspect
Sea hedgehog varies in size from 6 cm to 30-40 cm. Like the sea stars have a symmetry called pentamerism. They have 5 approximately spherical bodies of different dimensions that radiate to the center axis.
The shape of their body sometimes varies with oval shape with a degree of bilateral symmetry. Due to the activity the lower part is slightly flat, and the upper part can be slightly bulging.
This irregular shape has evolved to allow animals to penetrate into sand or other accessible places. The internal organs are covered with a thin layer of derma and spiderma.
Sea hadgehog have five pairs of ester glands lying around the mouth which are the main organs of breathing.
The bottom part, the one that meets the soil, contains the oral cavity. The thorns are long and sharp to protect the body of the predator.
It is not very clear, but it seems that in some species these spines contain venom. The common sea hedgehog have thorns of 1-3cm in length and 1-2mm in thickness.
In the Caribbean are sea hedgehogs that have thorns between 10 and 30 cm in length.
Sea Hedgehog’s Behavior
At first sight, the sea hedgehogs seem incurable to move. The most visible sign that they live is thorns.
Most turn their thorns to the point of touch to defend themselves from potential predators. The hedgehogs have no eyes on sight, feet or other means of locomotion, but they can move freely on hard surfaces with the help of spines.
The nervous system is relatively simple. He has no brain. The nerve center is made up of a large, non-finer ring that surrounds the oral cavity in the interior.
They are sensitive to touch, light and chemicals.
Sea Hedgehog’s Reproduction
In most cases the eggs float freely in sea water, but some species keep them between thorns thus providing protection.
The fertilized egg develops in less than 12 hours. Initially, a ball of cells appears to turn into a larva.
The larva has elongated shape and does not need to feed.
It may take several months for the larva to develop.
First begins with the formation of the outer surface around the mouth and anus that are almost in the same area. Some species reach maturity after 5 years.