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...
Elephants have one of the longest gestation period among mammals. They are pregnant for a period of around 22 months. After the 22 month gestation, they giver birth to a calf â¦ that is approximately 250 pounds heavy and stands at around 2.5 feet tall.1 person found this useful.or example Elephants have a gestation period of 22 months where as polar bears one of only 8 months.