A few scientists are dedicated to researching mysterious unclassified beasts which other scientists refuse to believe exist. While these cryptozoologists keep an open mind about their object of study, they are quick to point to cases in which the skeptics were proved mistaken. For example, the pygmy hippopotamus, once claimed to be extinct, was found to exist in East Africa. The giant squid was dismissed as the product of an overactive imagination until a specimen was washed up on a beach in 1873.

The word "they" in the first paragraph refers to