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The traditional hypothesis of cetacean evolution, first proposed by Van Valen in 1966, [9] was that whales were related to the mesonychians, an extinct order of carnivorous ungulates (hoofed animals) that resembled wolves with hooves and were a sister group of the artiodactyls (even-toed ungulates). This hypothesis was proposed due to ...
First tree sloths and hippopotami, diversification of grazing herbivores like zebras and elephants, large carnivorous mammals like lions and the genus Canis, burrowing rodents, kangaroos, birds, and small carnivores, vultures increase in size, decrease in the number of perissodactyl mammals. Extinction of nimravid carnivores.
Whales evolved from land-living mammals, and must regularly surface to breathe air, although they can remain underwater for long periods of time. Some species, such as the sperm whale, can stay underwater for up to 90 minutes. [2] They have blowholes (modified nostrils) located on top of their heads, through which air is taken in and expelled.
Basilosaurus (meaning "king lizard") is a genus of large, predatory, prehistoric archaeocete whale from the late Eocene, approximately 41.3 to 33.9 million years ago (mya). ). First described in 1834, it was the first archaeocete and prehistoric whale known to scienc
This has been called "shoot-and-salvage" because of the high-rate of loss due to whales sinking, lines breaking, etc. The first such whale hunting ship was the steamer Mabel Bird, which towed whale carcasses to an oil processing plant in Boothbay Harbor. At its height in 1885 four or five steamers were engaged in whale fishery at Boothbay ...
The larynx evolved when the first land vertebrates started breathing air and needed to separate food from air to prevent choking. Whales evolved from land mammals roughly 50 million years ago.
The first fully terrestrial vertebrates were reptilian amniotes — their eggs had internal membranes that allowed the developing embryo to breathe but kept water in. This allowed amniotes to lay eggs on dry land, while amphibians generally need to lay their eggs in water (a few amphibians, such as the common Suriname toad, have evolved other ways of getting around this limitation).
Coen Elemans, from the University of Southern Denmark, led a team that studied the carcasses of three whales that had died after being stranded, representing three different baleen whale species ...