Not only cows, elephants, giraffes and hippopotami have calves but glaciers have calves, which is the action of great chunks of ice breaking off glaciers and falling into the water.

Ice calving occurs when these large masses of ice separate from the end of a glacier. It happens because the forward motion of the glacier makes the end point unstable. We call these resulting chunks of ice "icebergs." Icebergs are also classified as a growlers, bergy bits, or a crevasse wall breakaways.

Calving of glaciers is often accompanied by a loud cracking or booming sound before blocks of ice, up to 200 ft high, break loose and crash into the water. There is a deep resonant sound as an explosion also accompanied by dangerous waves.

There are calving events which are very popular and major tourist attractions in Alaska. Surfers will actually get towed in by jet ski then wait for an iceberg to calve so they can surf the waves which are produced. These waves can reach 24 feet high.

The next calving events in Alaska will be held in February and March of 2018.

More Info: en.wikipedia.org