Square Feet. The square foot is a unit of area used in the imperial and U.S. customary measurement systems. A square measurement is the two-dimensional derivative of a linear measure, so a square foot is defined as the area of a square with sides 1 ft in length.
http://wiki.answers.com/Q/How_long_is_a_black_rhino_pregnant_for. A Black Rhino is pregnant usually between 419 and 478 days, or 15 to 16 months. The mother will give birth to a single calf, weighing in on average 35 to 50 kg, (about 80 pounds). The calf will stay with it's mother anywhere from 2 to 3 yea...
Giraffes, which are sizable animals, have an average gestation of 435 days, rhinoceroses have an average period of 450 days, and elephants, the largest land mammals, have an average period of 645 days. The term for how long an egg takes to hatch is often referred to as an incubation period.