Nurse Shark Bite: Understanding Risks and Treatment Steps

Nurse sharks are generally docile in nature. However, they possess strong jaws with thousands of tiny, serrated teeth and are fully capable of biting when provoked or disturbed. Nurse shark bites are not common, but they can occur, particularly in situations where humans inadvertently threaten or annoy them during diving or snorkeling activities.

While nurse sharks are not aggressive by nature, misconceptions persist due to their appearance and the word “shark” in their name, which often carries a negative connotation. Nurse sharks prefer to avoid human interaction, and most bites result from defensive behavior rather than predatory.

Understanding the behaviors that could lead to a bite and how to respond appropriately if an incident occurs is crucial.

What Are Nurse Sharks?

Nurse sharks (Ginglymostoma cirratum) are a species of bottom-dwelling sharks known for their sedentary nature. They tend to be inactive and rest during the day but become more active at night.

They possess a robust, yellowish to dark brown body ranging in length from 7.5-9.75 feet (2.1-2.7 meters) on average and weigh about 200 – 330 pounds (90-149 kilograms) with two rounded dorsal fins and an elongated caudal (tail) fin. Females are slightly larger than males.

Their broad head and small eyes are complemented by a set of strong jaws fringed with serrated teeth.

Typically found in shallow, tropical, and subtropical waters, nurse sharks favor coral reefs, mangroves, and seagrass beds. These environments provide ample food sources, including fish, rays, squid, octopus, crabs, lobster, shrimp, sea urchins, snails, and other benthic organisms. The nurse shark’s strong suction ability enables it to extract prey from tight spaces within the reef.

Nurse sharks play a crucial role in their ecosystems as predators. They help to maintain the balance by preying on species that are abundant, thus preventing overpopulation and ensuring the health of the coral reefs where they live.

Interactions between nurse sharks and humans are relatively infrequent. These sharks are generally docile, spending much time resting on the bottom. However, they can bite defensively if disturbed or harassed, with very few unprovoked attacks on humans recorded.

While not targeted by fisheries, nurse shark populations in some regions have declined due to habitat degradation and bycatch. They are classified as “Data Deficient” on the IUCN Red List.

How Dangerous Are Nurse Shark Bites?

@sharkslutz via Reddit

Nurse sharks are typically less aggressive than many other shark species and are not usually considered a threat to humans. However, they are capable of biting humans if provoked or disturbed. While nurse shark bites may not usually be fatal, they carry sharp, serrated teeth in powerful jaws and can inflict serious tissue damage.

Nurse Shark Attack Statistics: Rare But Can Occur

According to recent reports from the International Shark Attack File, there have been around 51 provoked bites and 5 unprovoked bites by nurse sharks worldwide before 2022.

As George Burgess, curator of the File, explains, “There have been 51 confirmed provoked bites by nurse sharks worldwide and five unprovoked bites” (Sacramento Bee).

So, while nurse shark attacks are still considered uncommon, they can and do occasionally occur. The provoked bites often result from humans accidentally disturbing or provoking the sharks, while the unprovoked bites likely stem from the nurse sharks’ nature and feeding behaviors. Nonetheless, most human-shark encounters remain safe.

Bite Force and Severity

The bite force of a nurse shark is not thoroughly documented, but their strong jaws can clamp down with significant strength.

An important aspect to consider is that, unlike other sharks that release after biting, nurse sharks have been known to hold on to their bite due to their gripping nature. This can complicate the injury and make the release of the shark from the victim more difficult.

Why Do Nurse Sharks Bite?

Nurse shark bites generally occur for one of three reasons:

Provocation and Accidental Encounters:

Most nurse shark bites happen when humans inadvertently provoke them. For instance, if someone steps on a nurse shark or disturbs it while it’s resting, the shark may bite as a defensive reaction.

Additionally, incidents have been reported where individuals were bitten after touching or bothering the sharks in their natural habitat. These actions can make nurse sharks feel threatened, which may trigger a bite.

Feeding Habits and Mistaken Identity:

Nurse sharks suck up their food using strong suction and have teeth designed to crush and grind, not slice. Sometimes, a nurse shark may mistake a hand or foot for its typical prey, such as fish or sea urchins, especially if bait or food is present in the water.

Triggering Behaviors:

Certain behaviors can increase the likelihood of a bite. Nurse sharks are more prone to biting if they feel cornered or are harassed. For example, when divers or swimmers attempt to feed or handle them, it can provoke an aggressive response.

Additionally, nurse sharks might bite if they mistake irregular movements in the water as a sign of injured prey.

By understanding these behaviors and avoiding actions that might stress or threaten nurse sharks, humans can greatly reduce the chances of an unfavorable encounter with these marine animals.

What Should You Do Immediately After a Nurse Shark Bite?

If someone is bitten by a nurse shark, follow these first aid steps:

  • Control Bleeding: Use a clean cloth, bandage, or gauze to apply firm, steady pressure directly on the bite area. This action helps to control bleeding. If the wound is on an arm or leg, elevate the limb above the heart level to slow blood loss.
  • Clean the Wound: Gently rinse the wound with fresh water to remove any debris. Avoid using hydrogen peroxide, as it can harm tissue and delay healing.
  • Cover the Wound: Cover the bite with a sterile bandage after cleaning. Keep the wound clean and dry to prevent infection.
  • Remain Still: Encourage the injured person to stay calm and still. Excessive movement can exacerbate bleeding and damage.
  • One should seek medical attention immediately, even for a small bite. Nurse shark teeth can leave bacteria that could cause infection.

If the bleeding doesn’t stop, there is severe pain, or the person feels faint or breathless, it’s critical to get to an emergency room or call emergency services without delay.

Remain Calm: A person’s tendency might be to panic, but remaining collected is crucial. Panic can accelerate the heart rate, leading to increased blood flow to the injury. A calm demeanor can also help the injured person tolerate pain better until medical help is reached.

How Are Nurse Shark Bite Wounds Treated?

When someone is bitten by a nurse shark, the first step is prompt and thorough cleaning of the wound. They should rinse the area with fresh water to remove any debris and to observe the extent of the injury. If bleeding occurs, apply direct pressure to the wound with a clean cloth to control it. Do not attempt to close the wound.

Professionals like emergency medical technicians (EMTs), nurses, and doctors should assess the bite immediately. These medical professionals are responsible for evaluating the depth and severity of the injury, checking for any signs of broken teeth or tissue damage, and determining the appropriate course of treatment.

Possible Treatments and Interventions:

  • Cleaning: The wound is further cleaned with sterilizing solutions to reduce the risk of infection.
  • Debridement: Sometimes, dead tissue must be removed—this is called debridement.
  • Closure: If necessary, the medical team sutures the wound, but some bites are left open to heal.

For infection prevention, patients are often prescribed antibiotics. Some commonly used antibiotics include fluoroquinolones, 3rd generation cephalosporins, carbapenems, glycopeptides, and doxycycline, depending on the patient’s specific needs and any allergies they may have. (National Library of Medicine)

Follow-Up Care:

Patients are advised to monitor the wound for signs of infection, such as increased redness, swelling, or discharge, and to seek medical attention if they notice any of these symptoms.

Follow-up appointments are important to ensure proper healing and to address any complications that may arise. Regular bandage changes and wound checks are part of this follow-up care.

What Are the Risks of Infection From a Nurse Shark Bite?

When a person receives a bite from a nurse shark, there is always a risk of infection. Nurse sharks inhabit marine environments that host a variety of bacteria, including those that could cause infection in humans.

Types of Bacteria:
Nurse shark mouths may contain bacteria such as:

  • Vibrio, which thrives in saltwater.
  • Staphylococcus aureus, commonly found on skin.
  • Mycobacterium marinum, associated with fish and marine environments.

Infection Signs:
After a shark bite, individuals should be vigilant for signs of infection, which include:

  • Redness or swelling around the wound
  • Increased pain or tenderness
  • Pus or drainage from the injury
  • Fever or chills

It’s crucial to monitor the wound carefully because a delayed response to these signs could complicate the recovery process.

Treatment Options:
If signs of infection are present, immediate medical attention is required. Treatment may involve:

  • Cleaning and disinfection of the wound
  • Antibiotics to combat bacterial infection
  • Surgery if there is embedded material, such as shark teeth

In some cases, bites have led to multiple rounds of antibiotics, particularly if pieces of tooth are still in the wound. Early and appropriate treatment mitigates the chance of a more severe infection, highlighting the importance of monitoring any shark bite closely.

Can You Prevent Nurse Shark Bites?

Nurse sharks are generally not aggressive, and most bites result from humans disturbing them, for divers and swimmers to recognize that these creatures prefer to rest on the ocean floor and avoid interactions.

Here are some straightforward tips:

  • Maintain a safe distance: Always give nurse sharks plenty of space. Maintain a safe distance of at least 2 meters (6 feet).
  • Avoid disturbing them: Do not touch, chase, or corner nurse sharks, as this can provoke a defensive bite.
  • Be cautious during feeding times: Feeding times can excite sharks, making them less predictable.

Precautions for divers and swimmers should include:

  • Observation first: Spend time watching nurse sharks from a distance to understand their movements and behaviors.
  • Minimal splashing: Excessive noise and splashing can attract unwanted attention from sharks.
  • Dive with a buddy: Always have someone with you who can help in case of an emergency.

Regarding protective gear, while there is no specific equipment to prevent a nurse shark bite, wearing full-body wetsuits or dive skins may offer a layer of protection against potential nips.

By giving nurse sharks ample space, not chasing or touching them, and avoiding feeding times, safe coexistence with these docile yet powerful sharks is possible.

What Are the Long-Term Effects of a Nurse Shark Bite?

A nurse shark bite can result in a range of long-term effects. While nurse sharks are typically nonaggressive, if provoked, they can inflict significant injuries due to their strong jaws and serrated teeth.

Physical Impacts:

  • Scarring: Almost all shark bites will leave some degree of scarring on the skin.
  • Mobility and Function: In severe cases, muscle and nerve damage can occur, leading to long-term mobility issues or loss of limb function.

Psychological Effects:


  • Victims may need physical therapy to regain strength and motion if their muscles are damaged.
  • For psychological trauma, counseling or therapy may support recovery.

While a nurse shark bite may not always be life-threatening, they can lead to lasting physical and psychological challenges. The rehabilitation process can help mitigate some of these long-term effects.

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