Whale shark: The biggest specimen ever reliably measured was 18.8 metres or nearly 62 feet long – that's bigger than a school bus! Basking shark: While they don't get quite as large as whale sharks, the largest basking shark ever reliably measured was 12.27 metres long, or just over 40 feet.
Whale sharks may be the largest sharks alive, but megalodons would likely eat them if given the chance. Whale sharks have been around in a similar form for nearly 245 million years.
Global water temperature dropped; that reduced the area where megalodon, a warm-water shark, could thrive. Second, because of the changing climate, entire species that megalodon preyed upon vanished forever. At the same time, competitors helped push megalodon to extinction – that includes the great white shark.
Is the megalodon still alive? 'No. It's definitely not alive in the deep oceans, despite what the Discovery Channel has said in the past,' notes Emma. 'If an animal as big as megalodon still lived in the oceans we would know about it.'
The largest white shark reliably measured was a 21-foot (6.4-meter) individual from Cuba. Bites on whale carcasses found off southern Australia suggest that white sharks as long as 25 or 26 feet (7 (1/2) or 8 meters) exist today.
The great white shark has killed the most humans resulting in 52 known fatalities, though roughly 300 unprovoked attacks are recorded from the great white.
The largest great white shark can reach lengths of up to 20 feet, although the majority are smaller than this. Females are generally larger than males, with the average size of a female great white shark reaching between 15-16 feet, and the average size of a male reaching between 11-13 feet.
The world's biggest recorded great white shark is a female affectionately named Deep Blue. She measures over 6 meters long (20 feet) and scientists think she may already be over 50 years old. She even featured in a Shark Week episode in 2014.
Because of these characteristics, many experts consider bull sharks to be the most dangerous sharks in the world. Historically, they are joined by their more famous cousins, great whites and tiger sharks, as the three species most likely to attack humans.
One of the most common and least dangerous sharks is the nurse shark. Nurse sharks are docile sharks and they grow to a maximum of 15ft long, compared to the equally-as-gentle whale shark (which can grow to around 62ft)!
Though impressive hunters, Bamboo Sharks have never attacked humans. Bamboo Sharks are so docile, they have been noted to let divers stroke and pet them.
Would a saltwater crocodile beat a great white shark?
A great white shark would win a fight against a saltwater crocodile. These deadly creatures are incredibly powerful, but the great white shark has an amazing advantage in the water. Not only would this animal probably notice the crocodile first, but it also has the speed to land a devastating attack.
There is no 40-foot great white shark, but there is one shark that grows that big – the modern-day whale shark (or even the second-largest species, the massive basking shark).
Those reports are generally considered to have been exaggerations. The largest confirmed white sharks come in right around 20 or 21 feet, firmly in the realm of Benchley's aquatic creature. The current top contender for the white shark crown is a female named Deep Blue.
The shortfin mako shark ( Isurus oxyrinchus) is found offshore in tropical and warm temperate waters of all oceans, but has been known to travel to cooler waters at times. It is very strong and the fastest known species of shark, reaching moving speeds of 31 mph (50 kph) with bursts up to 46 mph!
Porbeagles are one of the only shark species known to engage in playful behavior, just like dogs! They've been observed pushing floating objects and kelp around and chasing each other. They're very curious sharks and are likely to come check you or your boat out if you're in the water.
Nurse sharks often spend their days resting in groups of up to as many as 40 sharks in the wild. Some appear to be cuddling and snuggling while they rest.
According to the International Shark Attack File, humans have been subjects of 17 documented, unprovoked attacks by hammerhead sharks within the genus Sphyrna since AD 1580. No human fatalities have been recorded.
Some sharks such as the nurse shark have spiracles that force water across their gills allowing for stationary rest. Sharks do not sleep like humans do, but instead have active and restful periods.
Killer “whales,” which are actually dolphins, are apex predators, and their diet includes fish, squid, seals, sea birds and whales larger than themselves, according to the Natural History Museum in London. They are the only known predators of great white sharks.
This data suggests that mature adult megalodons had a mean length of 10.2 metres (about 33.5 feet), the largest specimens measuring 17.9 metres (58.7 feet) long. Some scientists, however, contend that the largest forms may have measured up to 25 metres (82 feet) long.