#9. Whale sharks are sharks and not whales In spite of the whale shark’s common name,
only one-half of it is biologically accurate. Whale sharks are sharks and not whales. Whales
are defined as aquatic placental marine mammals, of which the whale shark is not. Nevertheless,
the whale shark has been branded as a “whale” by virtue of its massive size. As a matter
of fact, the whale shark is the largest fish in the ocean.
As the largest non-cetacean animal in the world, whale sharks can weigh up to 47,400
pounds. That’s more than the weight of a bus, which can weigh as much as 40,000 pounds.
They also can be as long as 40 feet in length, which is about the length of a standard city
bus.
Throughout history, there have been reports of human encounters with supermassive whale
sharks. In 1915, Hugh M. Smith, an American Ichthyologist, described an animal captured
in a bamboo fish trap off the coast of Thailand. Although no official measurements were taken,
it is estimated that the creature, a whale shark, weighed 86,000 pounds and was as long
as 60 feet. There may be even more massive specimens deep beneath the ocean.
#8. Whale Sharks are filter feeders This is yet another characteristic that may
lend more justification to the “whale” portion of this creature’s common name.
Whale sharks are filter feeders, meaning that they feed by straining suspending matter and
food particles out of the water, typically bypassing the water through a specialized
feeding structure. The whale shark is one of the only three known sharks which are filter
feeders. Others include the megamouth shark and the basking shark.
When it comes to filter feeders, there are two types, active feeders and passive feeders.
The Whale Shark is an active feeder, meaning that it targets active concentrations of plankton
or fish. As for passive feeders such as the megamouth shark, they usually pick up whatever
they can get while they swim.
Whale sharks typically prefer food like plankton, krill, fish eggs, red crab larvae, and small
fish and squid. While active feeding, it uses active suction, opening and closing its
mouth in quick succession so as to suck in large volumes of water, which are expelled
by the gills. The food is filtered by modified gill rakers and subsequently digested.
#7. Whale Sharks are very slow swimmers Whale Sharks move at speeds no faster than 3
miles per hour. Compare this to the blue whale, which can move as fast as 30 miles per hour,
and the bottlenose dolphin, which can move as fast as 18 miles per hour. This slow rate
of movement helps whale sharks feed. But then again, it also makes them susceptible to attacks
from predators such as the blue marlin and the blue shark.
In spite of the whale shark’s slow rate of swimming, it can migrate across extremely
large distances. In fact, it can travel 8000 miles or more in three whole years. Like most
other animals, they migrate during the winter months to warmer waters so as to find food.
They generally prefer waters of a temperature around 70 degrees Fahrenheit.
Whale sharks inhabit all tropical and warm-temperate seas. They can be found in both coastal and
oceanic habitats. They have also been known to dive to depths of 6200 feet. And importantly,
they exist in two distinct populations. There’s the Atlantic sub-population and the Indo-pacific
sub-population. The latter holds 75% of all whale sharks.
#6. Female whale sharks can give birth to 300 young at once
Another characteristic of whale sharks which they share in common with mammals like whales
is that they give birth to live young. However, given that these whale sharks are ovoviviparous,
the actual process of fertilization, gestation, and birth is different from that of mammals.
Being ovoviviparous, female members of the species lay eggs, and fertilization takes
place internally. After fertilization, the females also carry the eggs inside them for
the entire period of gestation. When the eggs are ready, they hatch internally. And so,
the mothers give birth to live young.
A single mating session can result in the birth of a large number of young. However,
these births may occur at different intervals and not all at once. Young whale sharks are
known as pups and can be born 300 at a time. Out of these 300, not all of them get the
chance to grow to maturity. Many of them are picked off by the aforementioned predators,
the blue marlin and the blue shark. It doesn’t help that the mother leaves the young to fend
for themselves. Only about 10% of whale shark pups survive to adulthood.
#5. Whale sharks have dotted spots on their bodies
One of the most distinct characteristics of whale sharks is that they have white dots all
over their bodies. This allows divers, marine biologists, and fishermen to easily identify
them. These spots aren’t just there for aesthetics. Much like human fingerprints,
the pattern of these spots is different for different whale sharks and therefore serves
as a unique means of identification.
By taking pictures of these spots, researchers are able to keep up with whale sharks over
long periods of time and over long distances. This is how scientific facts like their reproductive
cycles, migratory habits, and travel speeds were determined. A common misconception is
that these spots are used to calculate their ages. However, this is not the case.
Other than just spots, some whale sharks have stripes on their bodies as well. Their skin
can be as much as 6 inches thick and can be very hard and rough to the touch. In addition
to this, the whale shark has three prominent ridges along its sides, which start above
and behind the head and end at the caudal peduncle.
#4. Whale sharks are an endangered species There’s no robust estimate for whale shark
population numbers. Nevertheless, they are considered an endangered species. This classification
arises due to the relentless hunting of these creatures by fisheries. Oil spills have also
cut down on their population numbers.
Even though mothers give birth to a lot of young, the fact that only ten percent of these
birthed young live to adulthood means that these population figures are likely to stay
low until the threats to these creatures are eliminated completely. One of the seemingly
innocuous activities humans partake in which affects these creatures’ population numbers
is ecotourism.
Whale sharks are quite popular, so they attract large numbers of ecotourists. These ecotourists
time the season feeding aggregations of these creatures, which happen in and around locations
like Western Australia, the Galapagos Islands, Mexico, Mozambique, the Philippines, Seychelles,
China, Qatar, and India. In fact, in 2011, about 400 whale sharks gathered off the Yucatan
Coast. It is the largest ever gathering of these creatures ever recorded. Since they
gather to feed, the presence of ecotourists could cause disruption, making them lose out
on important nourishment.
#3. Whale sharks are quite friendly In general, sharks aren’t known for being
friendly. However, the whale shark forms an exception. Whale sharks are known to be quite
friendly. They don’t harm divers or fishermen at all. Sometimes, they even allow certain
humans to ride on their backs.
In fact, in August 2020, an Arab man went viral when he posted a video of himself riding
a whale shark. The man, known as Abu Badi, performed the feat in the ocean of Yanbu,
Saudi Arabia, while his friends followed behind in a boat and recorded the whole thing.
The video generated several reactions of awe. However, there were those who expressed their
disapproval, as riding a whale shark could harm them, and being endangered, the concern
was extra serious. Whale sharks are considered so harmless that humans are actually a way
bigger danger to them than they are to humans. As such, conservation groups urgently express
the need for ecotourists and divers to avoid injuring these creatures. There have also
been efforts to free them from giant aquariums where they are held in captivity.
#2. Whale sharks live quite long Although not much is known about the reproductive
cycles of these creatures, it’s been determined that whale sharks have lifespans that far
outlast that of human beings. They live between 80 to 150 years. Growth rates are determined
using vertebrae growth bands. Though these bands were thought to form biannually, research
revealed they form every year, giving credibility to age estimates of these creatures.
Whale sharks exhibit some measure of sexual dimorphism. Although males grow faster than
females, males end up at a smaller maximum size than females do. Both genders also reach
sexual maturity quite late in life. Males typically tend to reach sexual maturity at
about 25 years old.
Although we’ve established that these creatures don’t take care of their young, they still
have an interesting way of trying to give them the best chances of survival. After mating,
females typically store sperm from the males and, at certain time intervals, fertilizes
the eggs on her own. And so, unlike other species which have fixed periods of fertilization,
gestation, and birth, the female whale shark could be at various stages of each of these
activities at a given time.
#1. Their mouths are their most important organs
Although another species of shark, the megamouth shark, has the benefit of having a name that
marks their most distinguishing feature, the whale shark’s mouth is nothing to write
off either. Given that they are filter feeders, their mouths are very large so as to facilitate
this behavior.
A 40 foot whale shark was once reported to have a mouth size about 5 feet across. Unlike
most other sharks, the whale shark also has its mouth at the front of its head rather
than the underside of its head.
Whale shark mouths can contain as many as 300 to 350 rows of teeth. They usually have a
total of about 3000 teeth. Each of these teeth is tiny and less than one inch long.
But again, as filter feeders, they don’t use these teeth to eat. As a matter of fact,
they can process about 6000 liters of water every hour. They expel a lot through their
gills, only keeping solid organisms smaller than about 2 centimeters in diameter.
Did you ever swim with or see Whale sharks? Let us know in the comment section below