A team of researchers made a puzzling finding — a group of three spider species called trashline orb-weavers have shockingly short internal clocks of just 17 to 19 hours, according to the Johns Hopkins News-letter.

For many college students, the start of a new day is marked by the shrill ring of an alarm clock in the morning and the end is dictated by our brains becoming too exhausted to process the textbook we are reading at the end of the night. But, in the absence of alarm clocks or a study schedule, when would we wake up and go to sleep?

Our sleeping and waking patterns are determined by a biological clock, regulated by the increase and decrease of hormones. In past studies, researchers have found that in extended periods of total darkness, organisms rely on their biological clocks, or circadian rhythms, to determine when they are active and when they rest.