“Sand worms” is a broad term encompassing various marine invertebrates found in sandy coastal environments. This article aims to clarify whether these creatures bite humans and what to know about such encounters. While many types of “sand worms” exist, some possess defense mechanisms that can result in a bite or sting.
Understanding “Sand Worms” and Their Biting Capability
Sand worms often refer to polychaete worms, a diverse group of segmented marine worms. Among these, bloodworms (Glycera dibranchiata) are well-known for their ability to bite. Bloodworms are found in shallow marine waters and can grow up to 35 cm (14 inches) long. They use an eversible proboscis, a retractable feeding structure, for defense and to capture prey.
Their proboscis has four hollow jaws made of protein, melanin, and copper. Connected to venom glands, these jaws allow bloodworms to inject venom when they bite. The venom immobilizes prey, like small crustaceans, and contains proteins similar to bee and wasp venom. Other polychaetes, like lugworms, are found in sandy environments but are not known to bite humans, though some can deliver a mild nip if threatened. Clam worms, another polychaete, also have jaws and can deliver a painful, non-venomous bite.
What to Expect if Bitten
A bloodworm bite is described as a sharp nip or sting, comparable in pain to a bee or wasp sting. After a bite, individuals may experience localized pain, redness, and slight swelling. Minor bleeding can also occur due to the worm’s four fangs.
While the venom is not severe enough to cause significant harm to humans, some individuals may experience an allergic reaction. Symptoms of an allergic reaction can include:
Hives.
Rash.
Difficulty breathing.
Swelling of the face, lips, or tongue.
Dizziness.
In rare cases, more pronounced symptoms like intense pain, spreading swelling, and blistering have been reported, sometimes taking weeks to resolve. If an allergic reaction or signs of infection develop (e.g., increased warmth, pus, persistent pain), seek medical attention.
Minimizing Bite Risk
To reduce the risk of bloodworm bites, caution is advisable when handling them. When collecting bloodworms for bait or working in common environments, wear protective gloves. This prevents direct contact with their biting apparatus and venom.
When digging in sandy areas where these worms reside, use tools rather than bare hands. While most encounters are harmless, awareness of their potential to bite if provoked can prevent an unpleasant experience. Individuals who frequently handle bloodworms, like fish farmers or anglers, may develop sensitivities or allergic reactions, making consistent glove use important.