Sea urchins are common marine inhabitants. A frequent question is whether these spiny creatures can “bite” like other animals. While sea urchins have a mouth, it functions differently than a biting jaw, and their primary protection involves other specialized structures.
Understanding Sea Urchin Mouths
Sea urchins have a unique feeding apparatus on their underside, called Aristotle’s Lantern. This structure consists of five calcified plates, or teeth, that converge centrally. These continuously growing teeth are used for scraping algae and other organic matter from rocks. The mouth’s position on the bottom of the urchin’s body, designed for grinding and scraping, makes it unsuitable for defensive biting.
Their Primary Defense Mechanisms
Sea urchins rely on two main physical features for defense: their spines and pedicellariae. The most prominent defensive structures are their spines, which vary in length, sharpness, and rigidity depending on the species. These spines serve as a physical barrier, deterring predators and providing protection against impacts. When disturbed or threatened, some species can orient their spines towards the perceived danger, creating a formidable spiky shield.
Beyond physical deterrence, many sea urchin species possess pedicellariae. These are small, pincer-like structures scattered among the spines, often appearing as tiny, jawed appendages on stalks. Pedicellariae can grasp, pinch, and in some species, even inject venom.
Consequences of Contact
Accidental contact with a sea urchin can result in immediate, localized effects. Punctures from spines cause sharp pain, often followed by redness, swelling, and a burning sensation. A common issue is spines breaking off and remaining embedded, leading to prolonged irritation. Pedicellariae, especially from venomous species, can cause a more intense reaction, delivering a mild sting, localized redness, swelling, and sometimes a temporary rash. While most sea urchin injuries are not life-threatening, embedded spine fragments can be difficult to remove and may cause secondary infections if not addressed.
Responding to an Injury
If contact with a sea urchin occurs, the initial step is to remove any visible spine fragments from the skin. Tweezers can be used for larger, more accessible pieces. Soaking the affected area in hot water, as hot as can be tolerated without scalding, for 30 to 90 minutes can help alleviate pain and soften the spines, potentially aiding their removal or absorption.
After spine removal, thoroughly clean the wound with soap and water to prevent infection. Seek medical attention if spines are deeply embedded, if signs of infection such as increased redness, pus, or fever develop, or if the pain is severe and persistent. Medical consultation is also advisable for symptoms such as muscle aches, weakness, or difficulty breathing, which could indicate a more significant reaction to certain venomous species.