Steller's sea cow is a tragic story of overfishing a species to the point of extinction. Their populations were entirely wiped out in 1768, only 27 years after scientific recognition. This extinction came about due to the amount of meat they could produce and how slowly they moved, making them easy prey. This species could grow up to 30 feet long and traveled in herds, feeding on sea grass. Steller's sea cow is a tragic story of overfishing a species to the point of extinction. Their populations were entirely wiped out in 1768, only 27 years after scientific recognition. This extinction came about due to the amount of meat they could produce and how slowly they moved, making them easy prey. This species could grow up to 30 feet long and traveled in herds, feeding on sea grass.