Report Abuse. An egg lives for around 12 hours after ovulation. Sperm can live for about five days inside the uterus, so providing those two time frames collide, it can be pretty soon after sex.
The tail arrangement is believed to have been a defensive weapon against predators. The term thagomizer was coined by Gary Larson in a 1982 Far Side comic strip, in which a group of cavemen in a faux-modern lecture hall are taught by their caveman professor that the spikes were named for the late Thag Simmons.
The term, coined in the 1980s by ecologist Eugene F. Stoermer, takes its prefix from the Ancient Greek word for human because its proponents believe the influence of humanity on the Earth's atmosphere and crust in the last few centuries is so significant as to constitute a new geological epoch.