Marine Mammal Protection Act Indian manatee, sea otter, polar bear, and Pacific walrus. Species not present in U.S. waters include the West African and Amazonian manatee, dugong, Atlantic walrus, and marine otter. In efforts to conserve and manage marine mammal species, the Service has appointed field staff dedicated to working with partners to conduct population censuses, assess population health, develop and implement conservation plans, promulgate regulations, and create cooperative relationships internationally. Various Marine Mammal Management offices are located on either coast. The Service's Marine Mammal Management office in Anchorage, Alaska is responsible for the management and conservation of polar bears, Pacific walruses, and northern
Mammal years ago. This tiny primate weighed 20–30 grams (0.7–1.1 ounce) and could fit within a human palm. Living mammal species can be identified by the presence of [[sweat gland]]s, including [[Mammary gland|those that are specialized to produce milk]] to nourish their young. In classifying fossils, however, other features must be used, since soft tissue glands and many other features are not visible in fossils. Many traits shared by all living mammals appeared among the earliest members of the group: For the most part, these characteristics were not present in the Triassic ancestors of the mammals. Nearly all mammaliaforms possess an