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.
Grizzly bears are even less productive: in 10 years, a male a female born today could grow to a population of only eight. By comparison, a pair of white-tailed deer could produce more than 1,400 descendants in 10 years. Bears generally live solitary lives, but can be found together during mating season. The average breeding age for female black bears is 3.5 years and for female grizzlies is 4.5 years. Males reach sexual maturity at roughly the same age as their female counterparts.