Orcas, like all mammals breathe air through
their lungs. But unlike humans, breathing is not an automatic reflex.
Each breath is a conscious act. When orcas come to the surface to
breathe they must quickly expel the used air in their lungs. This
creates a loud and characteristic sound, the "blow". Orcas breathe
usually in about 20 second intervals, in succession, 3 or 4 times,
and then remain submerged for a longer period of time. When the whales
are travelling fast they will breathe more often and at shorter intervals.
When orcas are resting, they take 3 or 4 breaths at short intervals
followed by a longer interval of about 3 minutes. Occasionally, orcas
hold their breath for as long as 12 minutes!