This video says about itself:
19 January 2015
In this short animation, produced for primary school children by Green.TV, supported by the Wellcome Trust, we look at the remarkable evolution of the whale from a land-based dog-like animal to the marine mammal that became the world’s largest ever creature.
From the Times of India:
Extinct whale’s 1 foot long tooth found on Australian beach
Subodh Varma | TNN | Apr 22, 2016, 04.21 PM IST
NEW DELHI: An Australian fossil enthusiast discovered a giant tooth of an ancient sperm whale that used to roam the seas five million years ago, munching up fish and even other whales. Murray Orr discovered the tooth at a beach at Beaumaris Bay near Melbourne, known for its vast trove of fossils. Orr immediately donated the fossil to Museum Victoria for further study.
The fossilised tooth is 30 centimetres (one foot) long and weighs three kilograms. This makes it larger than that of a Tyrannosaurus rex.
“After I found the tooth I just sat down and stared at it in disbelief,” Murray Orr said after the find was announced on Thursday by Museum Victoria, reports AFP.
“I knew this was an important find that needed to be shared with everyone.”
After studying the giant tooth, Museum Victoria said that it came from an extinct species of “killer sperm whale” which would have measured up to 18 metres (60 feet) in length and weighed some 40,000 kilograms.
“Until this find at Beaumaris all fossils of giant killer sperm whales were found on the west coast of South and North America,” Erich Fitzgerald, a paleontologist at the museum, told the Australian Broadcasting Corporation.
It is thought that these extict killer sperm whales deployed their massive teeth to munch on large animals, including fellow whales, unlike today’s sperm whales that eat a diet of squid and fish.
“If we only had today’s deep-diving, squid-sucking sperm whales to go on, we could not predict that just five million years ago there were giant predatory sperm whales with immense teeth that hunted other whales,” Fitzgerald said in a statement, AFP reported.
“Most sperm whales for the past 20 million years have been of the whale-killing kind. So, the fossil record reveals the living species to in fact be the exception to the rule, the oddball of the sperm whale family.”