Megalodon shark’sextinction may have ledwhales to grow in size

Whales are the largest living animal today and
it appears that the extinction of the 60-foot-
long Megalodon shark had something to do
with whales growing to their present-day size.
The Megalodon (Carcharocles megalodon)
was a fearsome predator of the ocean. It was
the largest shark known to have ever lived,
with teeth measuring nearly seven inches. It
is not yet clearly known what caused the
Megalodon to become extinct but researchers
now have a better idea of when this happened.
In a new study published in the journal PLOS
One on Oct. 22, researchers looked at the
records of 42 of the most recent fossils of the
ancient shark and employed a technique
known as Optimal Linear Estimation (OLE) to
determine when this animal died out.
The researchers found that the fearsome
predator of the ancient ocean likely died out
approximately 2.6 million years ago. The
Megalodon’s extinction likely happened in the
period between the Pliocene and Pleistocene
epochs, the time when the baleen whales
started to grow to their now gigantic sizes.
Baleen whales, which feed on tiny animals
that they filter out of the water using their
baleen, the comb-like structure in their
mouth, include the blue whale, the biggest
animal known today, which can grow over 89
feet in length.
The timing of the Megalodon’s extinction is
plausible because the carnivorous animal
preyed on dolphins and whales and its
absence would have paved way for the
primitive baleen whales, which were smaller
compared with their counterparts today, to
flourish.
“Our results suggest that C. megalodon went
extinct around 2.6 Ma.,” the researchers
wrote. “Furthermore, when contrasting our
results with known ecological and macro-
evolutionary trends in marine mammals, it
became evident that the modern composition
and function of modern gigantic filter-feeding
whales was established after the extinction of
C. megalodon.”
Study researcher Catalina Pimiento from the
department of biology at the University of
Florida in Gainesville said that the results
offer a basis for researchers to understand
the implications of the declining population of
the world’s top predators, including large
sharks.
“When you remove large sharks, then small
sharks are very abundant and they consume
more of the invertebrates that we humans
eat,” Pimiento said. “Recent estimations show
that large-bodied, shallow-water species of
sharks are at greatest risk among marine
animals, and the overall risk of shark
extinction is substantially higher than for most
other vertebrates.”

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