Here's why:
* Meat: Sea Cows were large, slow-moving, and relatively easy to hunt. Their meat was a valuable source of food for the people who lived on the islands where they were found.
* Blubber: The sea cow's thick layer of blubber provided a rich source of oil that could be used for fuel and cooking.
Unfortunately, this hunting, combined with the animal's inability to reproduce quickly, led to the Steller's Sea Cow's extinction within just a few decades of its discovery by Europeans.