Thus a pair of brown rats can produce as many as 2,000 descendants in a year if left to breed unchecked. (A rat matures sexually at age three to four months.) An average rat's life span is two to three years.5 A rat can tread water for three days and survive being flushed down the toilet.hus a pair of brown rats can produce as many as 2,000 descendants in a year if left to breed unchecked. (A rat matures sexually at age three to four months.) An average rat's life span is two to three years.
Late lice. The common head louse, Pediculus humanus capitis, may take as long as 14 days to hatch. Gilles San Martin/Wikimedia Commons. Hereâs some lousy news for parents of itchy-headed kids: Lice eggs can take 2 weeks to hatch in human hair, making standard 7-day delousing treatments ineffective in some cases.
The eggs develop and hatch approxiamately 10 days later. While lice treatments effectively kill lice, they also kill some, but not all, of the eggs. This is why it is important to Treat when the eggs hatch on day 10.ymphs: Once the louse hatches, it is called a nymph and is barely visible to the naked eye. The nymph cannot reproduce because it is not fully developed. After 12 days it becomes an adult. Adults: The adult louse can lay up to 4-10 eggs a day-starting another generation of lice.