April Fool’s may be over but many mistruths about sharks are still widely being circulated and have continued to fool people. Ian Chai from our Conservation Team is here to clear the air.
1. Sharks need to swim constantly or they will die
This is only partially true. It stems from the fact that about two dozen species of sharks (like the Great White Shark, Whale Shark and Mako Shark) use a method of breathing called ram ventilation: the shark needs to keep swimming forward to take in water, before ramming and filtering it through its gills.
On the other hand, some sharks breathe by buccal ventilation: they suck water into their mouth before pumping it over their gills using their cheek muscles. These sharks, such as the Tawny Nurse Shark, can alternate between activity and rest.
Then there are sharks that use both methods of breathing, such as the Sand Tiger Shark.
Click here to read more about this fascinating shark.
2. Sharks can smell a drop of blood in the ocean
Do you know that two-thirds of a shark’s brain is dedicated to its sense of smell? This is why sharks have a very acute sense of smell which allows them to detect prey up to 400 metres away. But to detect a drop of blood in the ocean is a little farfetched.
3. Sharks eat humans
Humans do not feature in the sharks’ natural diet. In fact, sharks hardly attack humans unprovoked. Statistics show that on average, only half of all reported shark attacks were unprovoked. Among these cases, the attacks tend to happen when humans exhibit risky behaviours, such as swimming during feeding times or swimming too close to the sharks.
Zebra Sharks are one species of sharks that are typically non-aggressive towards humans. Click here to read about the birth of Zebra Sharks in S.E.A. Aquarium, as documented by our aquarists.
4. Sharks can grow back their severed fins
Unlike sea stars which can regenerate their severed limbs, sharks are unable to regenerate severed fins. A finned shark thrown overboard will drown, bleed to death or be eaten by other sharks.
5. Sharks have no predators
We humans are the sharks’ greatest predator and threat. Each year, tens of millions of sharks are killed for their fins. The significant dip in shark numbers worldwide is also disrupting the ocean ecosystem.
6. Sharks have poor eyesight and are colour blind
Again untrue. Humans and sharks have a similar eye structure, but sharks have an additional layer of mirrored crystals located behind their retina. This increases the sensitivity of light detection which allows them to see better in low light conditions.
Scalloped Hammerhead Sharks are one species of shark with outstanding forward stereo vision. Due to the unique design of their heads, they are able to see 360 degrees in stereo and have a 32 degrees ‘binocular overlap’ in the front of their heads. Read more about the Scalloped Hammerhead Shark here and here.