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Dolphins’ “remarkable” healing abilities spur investigation

July 22, 2011
Courtesy of Georgetown University Medical Center
and World Science staff

A doc­tor has launched an in­ves­ti­ga­t­ion in­to what he calls the “re­mark­a­ble” abil­ity of dol­phins to heal from atro­cious wounds, say­ing hu­mans may ben­e­fit from the re­search.

With no ap­par­ent med­i­cal care, the finned mam­mals seem­ingly shrug off—and to­tally re­cov­er from—shark bites that look shock­ingly bad to a per­son, ac­cord­ing to the phy­si­cian, Mi­chael Zas­loff. “Com­pa­ra­ble in­ju­ries in hu­mans would be fa­tal,” said Zas­loff, of George­town Uni­vers­ity Med­i­cal Cen­ter in Wash­ing­ton, D.C., adding that dol­phins show lit­tle sign of pain from the wounds.

“Much about the dol­phin’s heal­ing pro­cess re­mains un­re­ported and poorly doc­u­ment­ed,” he went on. “How does the dol­phin not bleed to death af­ter a shark bite? How is it that dol­phins ap­pear not to suf­fer sig­nif­i­cant pain? What pre­vents in­fec­tion of a sig­nif­i­cant in­ju­ry? And how can a deep, gap­ing wound heal in such a way that the an­i­mal’s body con­tour is re­stored? 

Za­sloff, who has pre­vi­ously iden­ti­fied an­ti­mi­cro­bi­al com­pounds in the skin of frogs and in the dog­fish shark, re­ported his re­cent re­search in a let­ter pub­lished in the July 21 is­sue of the Jour­nal of In­ves­ti­ga­tive Der­ma­tol­o­gy. He in­ter­viewed dol­phin han­dlers and ma­rine bi­ol­o­gists from around the world and re­viewed the lim­it­ed lit­er­a­ture avail­a­ble about dol­phin heal­ing.

Za­sloff pro­poses that dol­phins may lim­it blood loss by div­ing deep af­ter an in­ju­ry, which di­verts blood away from out­er ar­eas of the body and to­ward the cen­ter. As for the ap­par­ent in­dif­fer­ence to pain, it “clearly rep­re­sents an adapta­t­ion fa­vor­a­ble for sur­vival,” he wrote in the let­ter, but how the feat is man­aged is un­known.

How the an­i­mal keeps in­fec­tion at bay may be less of a mys­tery, he said, pro­pos­ing that the an­i­mal’s blub­ber holds the key. Blub­ber and its make­up have been stud­ied ex­ten­sively be­cause it ac­cu­mu­lates many man-made pol­lu­tants, Zas­loff said. It’s thus well doc­u­mented that blub­ber al­so con­tains nat­u­ral an­ti­bi­otics called orga­no­ha­lo­gens. Probably “the dol­phin stores its own an­ti­mi­cro­bi­al com­pound,” Zas­loff pre­dicts. “This ac­tion could con­trol and pre­vent mi­cro­bi­al in­fec­tion while at the same time pre­vent­ing de­com­po­si­tion around the an­i­mal’s in­ju­ry.”

Za­sloff al­so ex­plored the abil­ity of the dol­phin’s wound to heal in a way that re­stores the body con­tour. He said the dol­phin’s heal­ing abil­ity is less like hu­man heal­ing and more like re­genera­t­ion. “The re­pair of a gap­ing wound to an ap­pearance that is near nor­mal re­quires the abil­ity of the in­jured an­i­mal to knit newly formed tis­sues with the ex­ist­ing fab­ric of adipocytes [fat cells], col­la­gen and elas­tic fibers,” he wrote. “The dol­phin’s heal­ing is si­m­i­lar to how mam­ma­li­an fe­tus­es are able to heal in the wom­b.”

Brent Whit­a­ker, dep­u­ty ex­ec­u­tive di­rec­tor for bi­o­log­i­cal pro­grams at the Na­tional Aquar­i­um in Bal­ti­more, called Zas­loff’s let­ter “thought pro­vok­ing.” Zas­loff con­sulted with Whit­a­ker as part of his re­search.

“It makes sense that the der­mal tis­sues of the dol­phins would evolve mech­a­nisms to pro­tect them from the mi­crobes ev­er pre­s­ent in the wa­ter in which these an­i­mals live,” Whit­a­ker said. “Other aquat­ic an­i­mals have de­vel­oped pro­tective strate­gies that al­low them to cope with wa­ter-borne mi­croflo­ra,” or pathogens. Zas­loff’s let­ter “sug­gests a un­ique and in­tri­guing hy­poth­e­sis which may beg­in to ex­plain how dol­phins, and per­haps oth­er cetaceans, sur­vive sig­nif­i­cant soft-tis­sue wounds in the wild with­out the aid of an­ti­bi­otics or clin­i­cal care,” he added.

“It is very clear from work­ing with ma­rine mam­mals that the abil­ity to heal is ‘en­hanced’ from what we see with ter­res­tri­al mam­mals,” said Leigh Ann Clay­ton, di­rec­tor of the De­part­ment of An­i­mal Health at the Na­tional Aquar­i­um, who al­so ad­vised Zas­loff. “Zas­loff pro­poses some fas­ci­nat­ing mech­a­nisms of ac­tion in heal­ing. It is ex­cit­ing to beg­in ex­plor­ing these mech­a­nisms more com­plete­ly.”

In his let­ter, Zas­loff pre­s­ents the case his­to­ries of two shark-bitten dol­phins, Nari and Ech­o, at the Tan­ga­looma Wild Dol­phin Re­sort in More­ton Is­land, Aus­tral­ia. The re­ports doc­u­ment the heal­ing pro­cess of the dol­phins with pho­tos to el­o­quently dem­on­strate how and how quickly two dol­phins heal from sev­ere shark in­ju­ries.

“The Tan­ga­looma dol­phin care team is con­tin­u­ously as­tounded at the remarka­ble nat­u­ral abil­ity of the dol­phins that vis­it us, in over­com­ing sev­ere shark bite in­ju­ries with what seems to be in­dif­fer­ence,” said Trev­or Has­sard, di­rec­tor of Tan­ga­looma. “We learn so much from the lives of oth­er an­i­mals. Per­haps Zas­loff’s con­tri­bu­tion will br­ing the dol­phin’s remarka­ble heal­ing ca­pa­ci­ties to the at­ten­tion of the med­i­cal re­search com­mun­ity.”

“My hope is this work will stim­u­late re­search that will ben­e­fit hu­mans,” said Zas­loff. “I feel rea­sonably cer­tain that with­in this an­i­mal’s heal­ing wounds we will find nov­el an­ti­mi­cro­bi­al agents as well as po­tent an­al­ge­sic com­pounds.”


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A doctor has launched an investigation into what he calls the “remarkable” ability of dolphins to heal from atrocious wounds, saying humans may benefit from the research. The finned mammals, with no apparent medical care, seemingly shrug off—and totally recover from—shark bites that look shockingly bad to a person, according to the physician, Michael Zasloff. “Comparable injuries in humans would be fatal,” said Zasloff, of Georgetown University Medical Center in Washington, D.C., adding that dolphins show little sign of pain from the wounds. “Much about the dolphin’s healing process remains unreported and poorly documented,” he went on. “How does the dolphin not bleed to death after a shark bite? How is it that dolphins appear not to suffer significant pain? What prevents infection of a significant injury? And how can a deep, gaping wound heal in such a way that the animal’s body contour is restored? Zasloff, who has previously identified antimicrobial compounds in the skin of frogs and in the dogfish shark, reported his recent research in a letter published in the July 21 issue of the Journal of Investigative Dermatology. He interviewed dolphin handlers and marine biologists from around the world and reviewed the limited literature available about dolphin healing. Zasloff proposes that dolphins may limit blood loss by diving deep after an injury, which diverts blood away from outer areas of the body and toward the center. As for the apparent indifference to pain, it “clearly represents an adaptation favorable for survival,” he wrote in the letter, but how the feat is managed is unknown. How the animal keeps infection at bay may be less of a mystery, he said, proposing that the animal’s blubber holds the key. Blubber and its makeup have been studied extensively because it accumulates many man-made pollutants, Zasloff said. It’s thus well documented that blubber also contains natural antibiotics called organohalogens. Probably “the dolphin stores its own antimicrobial compound,” Zasloff predicts. “This action could control and prevent microbial infection while at the same time prevent decomposition around the animal’s injury.” Zasloff also explored the ability of the dolphin’s wound to heal in a way that restores the dolphin’s body contour. He said the dolphin’s healing ability is less like human healing and more like regeneration. “The repair of a gaping wound to an appearance that is near normal requires the ability of the injured animal to knit newly formed tissues with the existing fabric of adipocytes [fat cells], collagen and elastic fibers,” he wrote. “The dolphin’s healing is similar to how mammalian fetuses are able to heal in the womb.” Brent Whitaker, deputy executive director for biological programs at the National Aquarium in Baltimore, called Zasloff’s letter “thought provoking.” Zasloff consulted with Whitaker as part of his research. “It makes sense that the dermal tissues of the dolphins would evolve mechanisms to protect them from the microbes ever present in the water in which these animals live,” Whitaker said. “Other aquatic animals have developed protective strategies that allow them to cope with water-borne microflora,” or pathogens. Zasloff’s letter “suggests a unique and intriguing hypothesis which may begin to explain how dolphins, and perhaps other cetaceans, survive significant soft-tissue wounds in the wild without the aid of antibiotics or clinical care,” he added. “It is very clear from working with marine mammals that the ability to heal is ‘enhanced’ from what we see with terrestrial mammals,” said Leigh Ann Clayton, director of the Department of Animal Health at the National Aquarium, who also advised Zasloff. “Zasloff proposes some fascinating mechanisms of action in healing. It is exciting to begin exploring these mechanisms more completely.” In his letter, Zasloff presents the case histories of two shark-bitten dolphins, Nari and Echo, at the Tangalooma Wild Dolphin Resort in Moreton Island, Australia. The reports document the healing process of the dolphins with photos to eloquently demonstrate how and how quickly two dolphins heal from severe shark injuries. “The Tangalooma dolphin care team is continuously astounded at the remarkable natural ability of the dolphins that visit us, in overcoming severe shark bite injuries with what seems to be indifference,” said Trevor Hassard, director of Tangalooma. “We learn so much from the lives of other animals. Perhaps Zasloff’s contribution will bring the dolphin’s remarkable healing capacities to the attention of the medical research community.” “My hope is this work will stimulate research that will benefit humans,” said Zasloff. “I feel reasonably certain that within this animal’s healing wounds we will find novel antimicrobial agents as well as potent analgesic compounds.”