Life as a dolphin isn’t always easy, and predators are always lurking in the shadows of the deep ocean. Throughout their lives, dolphins may suffer diverse injuries, from shark bites to boat propeller wounds to even sunburns! But dolphins must recover quickly if they wish to survive in the ocean. Good news for our slippery marine friends; they have super healing powers! How do they do it? Let’s look at what the science says.
When the predators attack
Sharks can be potentially dangerous for dolphins; you might be shocked by how common shark attacks are. A study from 2018 analyzed photos of 262 dolphins (from three different species) taken off the Northwest coast of Australia. Of these, 136 (52%) individuals had shark bite scars!
Dolphins have shown amazing abilities to recover from serious trauma. In the 1970s, scientists first noticed that superficial injuries like rake marks from conspecifics’ teeth disappeared quickly. A decade later, a paper documented that dolphins could survive large gaping bite wounds from shark attacks. To the researchers’ surprise, many dolphins were not only surviving but healing miraculously well & rapidly!
A lucky recovery
Meet Nari, a 12 years old bottlenose dolphin who was first observed with an impressive shark bite injury on February 13, 2009. The dolphin was caught to receive care and recover. It only took 40 days for Nari to heal from its deep wounds, and after day 42, he was returned to the ocean.
When humans strike
Even without sharks around, we humans are giving dolphins a hard time. Dolphins can get injured by boat propellers or entangled in fishing gear. These events may cause severe injuries.
This is a problem, especially in areas with many recreational vessels (to all boaters, please always be cautious and considerate if you know that dolphins are around – reducing your speed is the easiest way to avoid horrific injuries). Multiple organizations have reported boat propeller injuries on local dolphins.
In some cases, the injuries are too severe for an animal to survive. One tragic example involved an unlucky pilot whale off Tenerife. The wounded animal was euthanized after its tail was completely cut off by a boat propeller in 2019. We also documented the long agony of Fluker, a fin whale who suffered the loss of its tail due to two boat accidents.
In less severe cases, dolphins can show incredible recoveries. One example is Noah, a Sarasota dolphin who suffered propeller injuries in 2012 (below). The dolphin was able to recover and heal from its wounds. Sometimes the recovery can take only a couple of months, as featured in a 2010 study published in the journal Aquatic Mammals.
When the sun burns too strong
Dolphins can get sunburnt too! When a dolphin gets stranded on a beach or a mudflat, the sun may cause serious burns. A female dolphin from Scotland got stranded on a mudflat for a day back in 2016. As a result, the dolphin named Spirtle suffered an impressive burn wound on its flank. Two years later, the dolphin showed a white scar across its back, where the burn used to be. Spirtle’s recovery later allowed her to reproduce and live with her calf (pictured at the beginning of this post).
Spirtle, the bottlenose dolphin, before and after healing from a severe sunburn. Photos courtesy of Charlie Phillips/WDC
In Australia, a mother and calf bottlenose dolphin in the Port Adelaide estuary also suffered from injuries that were most likely bad sunburns during a stranding event in 2010. Researchers documented the healing progress of the mother and reported that after four months, the mom only had two white scars on her back. It is incredible to witness how well these animals recover from such severe wounds.
How do dolphins heal so well?
So how do dolphins recover so quickly? Can they avoid bleeding to death? How do they prevent a wound from becoming infected? And how do they deal with the pain? Research has provided some answers and even more questions.
Blubber – more than just fat
Especially after shark bites, wounds in dolphins do not only heal surprisingly quickly. They can even rebuild missing tissue, like blubber, thus restoring their normal body contour. Blubber is not just a layer of fat. It is a highly specialized tissue with an organized structure. Dolphins can regenerate the tissue, similar to what happens in mammalian fetuses. In contrast, in terrestrial mammals, soft-tissue healing is an uncoordinated process that leaves nasty scars. In a letter to the Journal of Investigative Dermatology, a medical researcher suggested that special stem cells are responsible for the regenerative abilities of dolphins, comparable to some amphibians that can regrow limbs.
And there’s more: dolphins’ blubber may contain natural antibiotics. This hypothesis would explain how dolphins prevent their wounds from becoming infected. The mouth of a shark is an ideal breeding ground for a whole collection of potentially infectious bacteria. These bacteria can infect an animal after a shark bite. However, dolphins rarely show signs of infection from these bites. We still do not understand the mechanisms behind these extra special healing abilities, but the letter above mentioned that some naturally-occurring organohalogens or special fatty acids could play a role in keeping infections in check.
Keeping the pain at bay
Even if a wound does not become infected, some of the injuries surely must cause a lot of pain, right? Dolphins are highly intelligent, sentient beings. Researchers believe they are capable of feeling pain the way we do. However, wounded dolphins don’t show obvious signs of pain. In an environment with many potential predators, it is not a good thing to appear weak and vulnerable. It has been suggested that a wound itself produces pain-relieving substances. Researchers must still confirm this theory and identify the molecules responsible for these potential pain-killing abilities.
Losing a lot of blood can also be dangerous in the ocean since predators like sharks can smell blood miles away. Dolphins’ adaptations to their sea-dwelling lifestyle could help them not lose too much blood. When going for a dive, the blood flow to the body’s periphery is cut off and instead focused on essential organs. This mechanism could also prevent the blood flow to an injury while it clots.
Let’s hope future research will lead to more in-depth knowledge about the mechanisms behind dolphin survival skills. A recent study showed that whale sharks show similarly remarkable abilities to heal. With increased research efforts, perhaps humans will be able to benefit from the same abilities e.g. new antibiotics or painkillers.
Coral reefs are underwater pharmacies
Besides their natural healing abilities, dolphins can rely on other sea creatures for help as well. One example has even made it into the first episode of Blue Planet II. Dolphins can rub themselves against certain species of coral and sponges. Like a sacred ritual, the dolphins visit the places where they grow at certain times and even queue to take turns. These corals and sponges covered in antimicrobial mucus can cure inflammations and skin diseases.
It is unknown how the dolphins first discovered these medical benefits. However, young dolphins are learning these secrets from their mothers. This behavior was observed in a wild population of Indo-pacific Bottlenose dolphins in the red sea. Scientists have been studying this particular population since 2009. Imagine what other secrets marine researchers could discover in the future…
Zasloff, M., 2011. Observations on the remarkable (and mysterious) wound-healing process of the bottlenose dolphin. Journal of Investigative Dermatology, 131(12), pp.2503-2505.
Thank you for reading our post! If you are interested in dolphin biology, make sure to check our other posts:
Hanna is a biologist from Germany with focus on marine mammals. During her university days she was involved in research projects in Italy, Australia and also Iceland. This is where she has spent most of her time since receiving her Master’s degree. Here she has been working as a naturalist for whale watching companies in different parts of the country. Since starting to work as a guide and lecturer on polar expedition cruises in 2017, she has been migrating between Iceland and Antarctica sharing her passion for cetaceans and seals.