Big male giraffes can measure up to 18 feet from head to toe, including a 61∕2-foot-long neck. Although it may seem that the giraffe would have trouble renewing the air in each breath and reinhaling used air, this is not the case.

Physiological examinations have revealed that giraffes do not have a larger dead space than other mammals, because giraffes increase the air’s tidal volume. The average air speed in the trachea of a giraffe is 6 feet per second, which is approximately twice as fast as in humans. The airflow of giraffes’ windpipes is so fast that it is close to being turbulent, but that would increase the air resistance and thus reduce the breathing efficiency.

The windpipe diameter of a giraffe is only around 1.6 inches, and in proportion to its length, it’s remarkably narrow compared to other mammals. Scientists think that the dead space in the windpipe would be too large if the diameter was any wider.