Stella the Steller's Sea Cow
Status: Know to science.
Extinct 1768.

Apart from whales, Steller's Sea Cow was the largest mammal to survive into modern times. At over 8 metres or 26ft long and weighing over 10 tonnes, this gentle giant now enjoys swimming up and down the shallows in the Sea of Tranquility.

Stella the Steller's Sea Cow

Reason for Extinction:

Steller's Sea Cows were some of the most docile and friendly creatures you could hope to meet. However, they were also, unfortunately, good to eat and were soon hunted to extinction by man.