Oceanic Whitetip Sharks - the Sharks that have Eaten the Most People!
Perhaps fortunately for us, we humans will seldom encounter oceanic whitetip sharks simply because they are pelagic (open ocean) sharks, and seldom come near the shallow waters where we bathe.
Ship-wrecked mariners tell a different tale, or would if they actually survived to make it to land.
Oceanic whitetip sharks (Carcharhinus longimanus) have been responsible for the deaths of thousands of people, in various shipping or air disasters over the centuries. Historically in all the worst shark attacks, oceanic whitetips have been right there.
This makes them possibly the most dangerous shark of all, and certainly the shark responsible for more human deaths than any other.
Yet it is a shark we rarely hear about. Great white, tiger and bull sharks frequently hit the headlines when they interact with humans, either through shark attacks, encounters, or even just sightings.
This is because almost all oceanic whitetip shark attacks take place far from land, where there are few witnesses, and ever fewer survivors.
An oceanic whitetip was implicated in the tourist deaths by shark attack in the Red Sea in late 2010, but it's involvement was not proven.
What do Oceanic whitetip sharks look like?
As you an see from the photo here. the two most distinguishing features of c.longimanus is their long, wing-like pectoral fins, and the white fin tips that gave them their common name.
Big fish, the males typically reach 1.8m (5ft 11in) while the females of the species reach 1.9m (6ft 3in).
The maximum recorded length of an oceanic whitetip shark is 4m (13ft).
Their upper back colours are typically blue, grey, bronze or brown, depending on region. Their undersides are white or yellow.
If you are in the unfortunate position of finding yourself in deep water, far from land, don't worry about the colour of this shark or where it came from. Concern yourself instead on its white tipped elongated dorsal fin.
Whitetips are normally solitary sharks, preferring their own company to that of others, but when they get excited, others tend to find them and they congregate together.
While they are not aggressive sharks, in an excited state they can enter what is called a 'feeding frenzy'.
If you are in the water at the time, your chances of escaping unharmed are pretty slim.
Oceanic whitetip sharks, when in a 'feeding frenzy' will bite and snap at anything and everything in the water, and repeatedly attack, causing fatal wounds very quickly.
They have a pretty serious set of teeth on them. Their upper teeth are triangular, serrated like a bread knife and exceedingly sharp.
Their lower teeth are smaller, more pointed and needle-sharp.
Common names of Carcharhinus longimanus
- Oceanic whitetip shark
- Whitetip shark
- white-tipped shark
- Whitetip whaler
- Brown Milbert's sandbar shark
- brown shark
- nigano shark
Where do oceanic whitetip sharks live?
They like the warmer waters and oceans of the world.
Scientists tell us they prefer waters above 18C (64F), preferably as high as 28C (82F).
If this is so, this does not explain why a dead one was washed up on a beach in Sweden. The cold North East Atlantic waters is the last place you would expect to see a whitetip, dead or alive.
You can see from the world map that oceanic whitetip sharks tend to stick to the central equatorial belt, but stretching also 45οN and 43οS.
They are commonly found at a depth of 150m (490ft) underwater, although occasionally they have been spotted close to shore in shallow waters around Hawaii, or in the Red Sea - areas where a deep continental shelf or other deeper waters are nearby.
They are known to go to the surface and stick their heads out, better to see where prey might be.
They feed both day and night, unlike many other sharks that only feed at night.
What do oceanic whitetips eat?
Like all the big sharks of the ocean, C. longimanus see it as their job to clean up the oceans.
So, quite apart from what could be considered to be their normal diet of cephalopods (squid, octopus, inkfish etc), fish, sea turtles, birds and crustaceans, they are also known to eat the faeces of bigger mammals, as well as anything dead or dying that they come across, including marooned humans.
And yet divers have been filmed diving with oceanic whitetips, with no signs of aggression from the sharks.
They are only dangerous when whipped up into a frenzy as occasionally happens when this fish joins a group, and carrion or perhaps just something that might be food, is present.
An uninjured person in the water can easily keep a whitetip at bay, though they will keep returning, just like a vulture waiting for its intended victim to die.
Unfortunately when hours stretch into days, it is much harder to keep them away long enough until rescue comes. Sleeping is impossible, as a sleeping body is food.
It is reckoned nearly 900 military personnel lost their lives to oceanic whitetip sharks in the USS Indianapolis sank during World War II.
Even today, these sharks follow ocean-going ships, almost as if they are just waiting for disaster to strike.
How do oceanic whitetips reproduce?
C. longimanus are viviparous, which means that the shark pups grow inside the mother and are fed by a placental sac.
Gestation typically takes a year, and she gives birth to any number up to 15 pups at any one time.
Oceanic whitetip shark pups are typically 2ft (0.6m) long at birth.
They normally mature at aged around 6 or 7 years, and can live for up to 22 years.
Are oceanic whitetip sharks endangered?
Yes they are.
While the IUCN lists them as 'vulnerable' in some parts of the world, in other areas they are 'critically endangered'.
They are hunted for their meat, for their fins (for sharks fin soup), for the vitamins in their liver oil, and for their skin which is used to make leather.
Studies have shown their overall numbers have dropped by 70% over the past few years.
Fish that are slow to mature and have a low birth-rate such as the oceanic whitetip shark can easily be overfished and fished out of the ocean, and steps need to be taken in order to offer them some protection.