Which of these aquatic animals is a mammal ?
[A] Shark [B] Squid [C] River Dolphin [D] Octopus
[C] River Dolphin
River dolphins are a widely distributed group of fully aquatic mammals that reside exclusively in freshwater or brackish water. They are an informal grouping of dolphins, which is a paraphyletic group within the infraorder Cetacea.
What is a large semi-aquatic rodent native to Canada, much of the United States, and parts of northern Mexico that constructs homes out of sticks, twigs, and mud in lakes or streams?
