Great whites prove healthy despite toxins in blood

Posted by Imogen Searra on 3 April 2019

Great white sharks are some of nature’s most misunderstood marine animals, but also some of the toughest. For years, scientists have been proving the natural resilience of these animals. Recently, a study was published revealing that great white sharks in South Africa are living with high levels of heavy metals in their blood.

Being on top of the food chain means that great whites are exposed to heavy metals quite a bit through their food sources. This, coupled with a long lifespan, means exposure is constant.

Marine biologists from the University of Miami studied blood samples from 43 great whites captured and released during an expedition in South Africa in 2012. The individuals from the sample were tested for the presence of 14 heavy metals and 12 trace elements. The aim of the study was to see if the heavy metals and trace elements in white sharks had any influence on the sex, size, body condition or other health indicators. The heavy metals included lead and the trace elements included arsenic and mercury.

Image source: Alain Clark Miller


On average, the sharks where found to contain high levels of lead, arsenic and mercury in their blood. The levels of arsenic and lead are high enough that they would be fatal or seriously damaging to other animals.

The study also, however, revealed that the high heavy metal levels had no affect on the sharks’ growth and development. Their immune systems were seemingly unaffected too, based on the stable behaviour of certain immune cells in their bodies.

With the metal levels in their blood seemingly having no negative physical effects, the researchers in the study concluded that these sharks may have a mechanism that protects them from the harmful effects of heavy metal exposure.

To read the study in full, click here.


Image: Alain Clark Miller

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