Usually only 1 baby at a time. Sometimes twins are born but it is very rare. Female whales, known as a cow carry their unborn young 9 to 18 months. Most cows give birth to a baby every 2 to 5 years.
Though nostrils called blowholes. The blowhole is on the top of the head. This helps the whale breath when most of the body is underwater. Before taking a dive the whale fills its lungs with air. Then underwater it holds its breath. Sooner or later it needs to take a breath but first-VOOM-it blasts out stale air called a blow at 300 miles an hour.(480 km)