A new study indicates that Americans gained up to 15 IQ points after the addition of iodine to salt became mandatory. In an effort to prevent goiter related to iodine deficiency, authorities ruled that iodine be added to U.S. salt products in 1924. The iodine, in addition to eliminating goiter, appears to have had an unexpected result: smarter Americans.
At peak lactation a black bear cub consumes about 30 ounces of milk a day, and a brown bear cub takes about 45 ounces. Thatâs per cub, so a mom with a litter of two or three cubs could be producing three or four quarts per day â a difficult metabolic feat to sustain.
How do polar bears raise their young cubs to survive in the wild and why must they stay with them for so long? Mother polar bears are pregnant for about eight months at a time and they usually give birth about every three years. In order to become successfully pregnant, mother polar bears must gain at least 441 lbs or 200kg, to support her cubs.