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.
Pets can be a carrier for the lice but the lice cannot survive long on an animal. Reproduction. Females lay up to 400 eggs in their lifespan, which is spaced out to about eight eggs per day. These eggs hatch in one to two weeks. Life Cycle. Head lice begin as empty eggs called nits. They attach themselves near the root of the hair with a substance that is like glue and cannot be simply washed away. When the eggs hatch, the nymphs feed on blood from the scalp. Life Span. Nits, or lice eggs, can live for up to 10 days but will need to feed on human blood after hatching. Adult lice can live for up to one month on the head of a human but die within two to three days without body contact. The total life span of lice is 40 to 50 days, if you include the complete life cycle: egg, nymph and adult. Fun Fact