Sharks are immune to almost all known diseases
Sharks are the only animals that almost never get sick: they are immune to almost every known disease.
Their body frames are not made up of bones – they are made of cartilage, the tough, fibrous tissue that shapes our noses and ears. Instead of scales shark skins have small tooth-like spikes that are so sharp that shark skin has long been used as sandpaper.
It is thought that some types of big sharks, including the Great White, change sex when they reach a certain size: males become females to ensure survival of their species.
Although sharks are one of the most feared animals – the fear of sharks is called galeophobia – fatal attacks on humans are fairly rare in comparison to many other incidents. Fatal attacks by dogs outnumber sharks ten and more times per year and you are 50 times more likely to be hit by lightning. A shark attack comparison by PressExposure reads like this:
“The US has a population of 300 million, your odds of being a victim of a shark attack are 1 in 8 million. In comparison, your odds of dying from a fall down the stairs are 1 in 200,000. Your odds of dying from a wasp, bee or hornet sting are 1 in 5.9 million. Your odds of dying from a lightning strike are 1 in 4.3 million. Your odds of drowning in your bathtub are 1 in 800.000. Other causes of death with a higher probability then being attacked by a shark are: dying from an adverse reaction to antibiotics with the odds being 1 in 7 million, being killed by a falling object has odds of 1 in 400,000, being killed by an agricultural machine has odds of 1 in 500,000 and being killed in a motor vehicle accident has odds of 1 in 6,000.”
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For more about the real facts on sharks, see SharkWater
History of known shark tumors
Shark cartilage extract study
Article updated August 2010.