Introduction
Marine mammals are fascinating creatures. They are
mammals, like us, but they are descended from several
different groups of terrestrial mammals (including the
groups to which elephants, hippos, and bears belong to).
Today there are 3 orders of marine mammals, plus a few
species that belong to terrestrial mammal orders.
- The order Sirenia
is composed of manatees & dugongs.
http://www.worldwildlife.org/gift-center/Images/large-species-photo/large-dugong-photo.jpg
- The order Pinnipedia
is composed of true (earless) seals, sea lions, and
walruses.
http://gothamist.com/images/2005_03_seal-thumb.jpg
- The order Cetacea
is composed of toothed whales (such as dolphins) and
baleen whales (such as blue
whales).
http://preservingthesecretsoftheocean.wikispaces.com/file/view/ogcGR_lg_bluewhale.jpg/34305887/ogcGR_lg_bluewhale.jpg
- Sea otters & marine otters are marine mammals that
belong to a group of terrestrial mammals called
mustelids.
http://wiki-images.enotes.com/thumb/d/d4/Sea_otter_pair2.jpg/200px-Sea_otter_pair2.jpg
- Polar bears are not considered marine mammals by some
because they are not fully marine like the rest, and
because they only diverged from their terrestrial sister
species, Grizzly bears, about 1 million years ago. They
are ursids and belong to the order Carnivora (as do
mustelids).
http://a-z-animals.com/images/blog/pol1.jpg
(Horstmann-Dehn, 2012,
& Perrin, 2009)
I decided to make this webpage about marine mammals &
the physics of how they live in the ocean, not only
because I love marine mammals and I'm very interested in
them, but also because the sea is an environment that is
so different from our own (and from that of the ancestors
of all the groups of marine mammals). As such, not only is
the ocean interesting in itself, but it also presents many
challenges to mammals, producing a plethora of fascinating
adaptations. I only wish I had the time to investigate the
subject in more depth, and present to you more of the many
ways in which these wonderful creatures are adapted to
living in the sea.