Marine Mammals at the Zoo
technically not inside the Oceans exhibit, the Indianapolis Zoo's marine mammals share
one thing in common with their fishy cousins - a watery environment. The Zoo marine mammal collection includes Atlantic bottlenose dolphins
(which star in their own exhibit, the
Pacific walrus, polar bear,
California sea lions,
harbor seals and gray
seals. The seal and sea lion exhibit is near the entrance to Oceans,
while the polar bear exhibit is positioned just outside the exit from
Oceans. The walrus exhibit, including an underwater viewing theater,
is a bit farther on and leads directly to the Dolphin Adventure Pavilion.
Photo by Ellen Jackson
Marine mammals are a diverse group of
roughly 120 species of mammals that are primarily ocean-dwelling or depend on
the ocean for food. They include the cetaceans (whales, dolphins, and
porpoises), the sirenians (manatees and dugong), the pinnipeds (true seals,
eared seals and walrus), and several otters (the sea otter and marine
otter). The polar bear is also usually grouped with the marine mammals.
mammals evolved from land dwelling ancestors and share several adaptive
features for life at sea such as generally large size, hydrodynamic body
shapes, modified appendages and various thermoregulatory adaptations.
Different species are, however, adapted to marine life to varying degrees.
The most fully adapted are the cetaceans and the sirenians, whose entire
life cycle takes place under water, whereas the other groups spend at least
some time on land.
Photo by Rick Lang
marine mammal populations are
vulnerable or endangered due to a history of commercial exploitation for
blubber, meat, ivory and fur. Most species are currently protected from
commercial exploitation. The effects of climate change are also
threatening the sea ice home of the polar bear.
Since mammals originally evolved on land, their spines are optimized for
running, allowing for up-and-down but only little sideways motion. Therefore, marine mammals typically swim by moving their spine up and down.
By contrast, fish normally swim by moving their spine sideways. For this
reason, fish mostly have vertical caudal (tail) fins, while marine mammals
have horizontal caudal fins.
orphan dolphin sent to the Indianapolis Zoo in 2011
continues to do very well. Taz is growing up
quickly, loves training and interacting with
the marine mammal staff, and beginning this year, he is participating (at his speed, of course) in the
dolphin shows, doing little pirouettes and layouts. He has learned to beach and to arch,
an important behavior not only because it gives us a
chance to pose with him for photos with people, but
because we can weigh him on the scale and obtain more
consistent weight figures. Right now, he's doing
these new behaviors on the stage at the back of the
performance pool, but we expect him to become more active
in the shows as this not-so-little
dolphin continues to grow! The photo by trainer Abbie Mingus shows Taz with some visual
enrichment — something a little different, but we think
this is very interesting! He's looking at some
colorful items adhered on the glass.