Part 4: Marine Mammal Diversity I (Lecture 10: Carnivora, Pinnipedia)
To which Mammalian order to both polar bears and sea otters belong? Which other major group of marine mammals is often considered to be part of this order (but treated as a separate order in this course)?
Polar bears, like black and brown bears, are in the genus Ursa. How do polar bears differ from other members of this genus? Describe in terms of adaptations to both the marine and polar environment.
Where geographically speaking, would you find a polar bear? In which hemisphere will you never find a polar bear (except perhaps in a zoo)?
Compare the habitat, foraging range and denning/hibernation behavior of male vs. female polar bears.
How is the distribution of polar pinnipeds as well as their time spent nursing young affected by polar bears?
How do polar bears find ringed seals buried in caves?
In what direct way could global climate change threaten polar bear populations? Answer in terms of their lifestyle.
Describe how sea otters are adapted to a marine existence. Consider both movement through the water and thermoregulation.
Compare swimming in polar bears and sea otters, focusing on the limbs and motions they use for swimming.
Name some major foods in the sea otter’s diet. Describe how sea otters collect and eat these foods (i.e. what limbs do they use; how do they deal with hard shells and exoskeletons)?
Of what value is kelp itself to the sea otters? In what way do the otters themselves help maintain the kelp forest?
Compare the distribution of sea otters in the past (“historic range”) vs. the present, summarizing the major differences. What caused the near-extinction of sea otters along the west coast of the U.S. around 1900?
How are domestic cats a threat to sea otters?
To which order (sometimes considered a suborder of Order Carnivora) of mammals do seals, sea lions and walruses belong?
Know the names and members of the three families of Order Pinnipedia.
Describe the major differences among the physical features and methods of movement of the Phocidae, Otariidae and Odobenidae, being sure to indicate the appearance of each feature in each group (for a list of features, see your Lecture outline). Also, explain the adaptive value of these differences in terms of life-history differences (for example, amount of time on land vs. in water, etc…).
List the several major types of food resources for members in the Order Pinnipedia, and discuss the potential for diet differences among members of the same species.
Which seal species feeds almost entirely on krill, and how is it adapted to do so?
Which seal species is the only phocid to feed on birds and mammals? Name another of its key food resources for which it is specifically adapted.
Name the only pinniped known to feed on cetaceans.