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.
Use nit combs or cat flea combs to remove the lice and eggs. Because eggs can hatch for up to 10 days after they are laid, comb hair daily for two weeks after you find the last live head lice, to remove any young that have emerged.dult head lice are about 1/8 inch long, grayish, flattened, and wingless. Their legs are claw-like, designed to hold onto hair. These lice excrete partially digested blood which can appear as 'black dandruff'. Lice eggs, commonly referred to as nits, are whitish, oval and the size of a pinhead (1/30 inch long).