Usually, it's because the sperm gets into the fallopian tube before the egg is released. Once there, the sperm wait for an egg to arrive. After fertilization, it can take 5-10 days for the fertilized egg to begin to attach itself to the lining of the uterus. Pregnancy begins when this happens.
The arrangement of spikes originally had no distinct name; the term Thagomizer was coined in 1982 by cartoonist Gary Larson in his comic The Far Side, and thereafter became gradually adopted as an informal term within scientific circles, research, and education.
One example of this trend comes from a 1982 panel he penned wherein a caveman professor is giving a lecture to his caveman pupils about the dangers of the Stegosaurusâs tail, explaining âNow this end is called the Thagomizer after the late Thag Simmonsâ.