Threats to sea turtles are numerous and have caused many sea turtle species to be endangered. Of the seven extant species of sea turtles, six in the family Cheloniidae and one in the family Dermochelyidae, all are listed on the IUCN Red List of Endangered Species. The list classifies six species of sea turtle as "threatened", two of them as "critically endangered", one as "endangered" and three as "vulnerable". The flatback sea turtle is classified as "data deficient" which means that there is insufficient information available for a proper assessment of conservation status. Although sea turtles usually lay around one hundred eggs at a time, on average only one of the eggs from the nest will survive to adulthood. While many of the things that endanger these hatchlings are natural, such as predators including sharks, raccoons, foxes, and seagulls, many new threats to the sea turtle species are anthropogenic. Artificial lighting is a threat to adult and hatchling sea turtles. Sea turtles use the brightest horizon as a guide to the ocean. This was created by celestial lights reflecting off the ocean’s surface. With human development along the coast, artificial light sources are growing in abundance. Unfortunately, these human-made lights are brighter than celestial lights, causing sea turtles to move toward them. A sea turtle not going in the direction of the ocean is referred to as a disorientation event. Disorientations lead to an increased risk of predation, exhaustion, dehydration, and/or injury. These events are often fatal. Disorientations can be caused by any light source that is directly or indirectly seen from the beach. Also, heavily lit beaches may cause an adult to have a false crawl. This is when the female decides the beach is not suitable for her nest and goes back to the water. False crawls cause exhaustion for the adult and may lead to her releasing her eggs in the ocean. This would be fatal to all the eggs.