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.
16 Months of Patience. The white rhino is one of the largest of all rhino species, so it's not surprising that her large stature would lead to a long gestation period of 15 to 16 months. After the gestation period, the mother gives birth to a single calf weighing around 143 pounds.
Elephants has the longest pregnancy about 22 months. (Didelphis marsupialis); the rare water opossum, or yapok (Chironectes minimus) of northern South America and the eastern native cat (Dasyurus viverrinus) of Australia.