Photographic Study Reveals How Dolphins Survive Shark Attacks
Thousands of photographs have revealed how many of Australia’s dolphins are living with shark-inflicted wounds.
In one of the first studies of its kind, researchers from Flinders University collected and assessed thousands of photographs of dolphins in Australia to discover than many of them had serious scarring.
While some scars are from fights between dolphins and others are most probably from boat strikes, other abrasions appear to have been caused by sharp teeth.
In an article published in Ecology and Evolution earlier this month, researchers revealed how dolphins are surviving attacks from bull, tiger and white sharks in coastal waters across south, central, and north Queensland.
Researchers discovered high numbers of dolphins observed had evidence of shark-inflicted wounds. The study assessed thousands of photos taken from boat-based surveys, concluding that 33% of the 56 snubfin dolphins and 24% of 36 humpback dolphins identified show evidence of shark bites.
‘Gnarly’
Up until this study, little was known about the predation risk some dolphin species face from sharks or how frequently they survive these battles.
According to the researchers, the study reveals the importance of considering photographic coverage when assessing bite injuries on animals.
Caitlin Nicholls from the Cetacean Ecology, Behaviour, and Evolution Lab (CEBEL) at Flinders University tells Yahoo News Australia that some of the bite marks seen on dolphins were extremely “gnarly”.
Nicholls explains: “They’re semi-circle bite marks and you can see the punctures from their teeth. There’s often dragging from where the dolphin has wriggled away.”
While these bites would have been fatal for a human, dolphins have fast-growing, thick skin, enabling them to recover after attacks.
When researchers had access to photographs of the whole dolphin they were more likely to find evidence of scarring. A large proportion of the bites were on the mid-flank, just below the dorsal fin.
“If they get bitten in this area, we think they’re more likely to survive the attack,” Nicholls tells Yahoo News Australia.
“Whereas if they get bitten, maybe on their head or tail, it’s more likely to be a fatal attack because it would immobilize the dolphin and they wouldn’t be able to swim away.”
Image credits: All photos by Cetacean Ecology, Behaviour and Evolution Lab (CEBEL)/ Flinders University.
