Threats to sea turtles  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 have recently arrived and with   One of the greatest threats to the survival of hatchlings is artificial lighting. When a sea turtle hatches, its evolutionary instincts push it to move towards the brightest light in view, which naturally would be the sun or the moon, leading them toward the ocean horizon and into their new ecosystem. However, due to the continual expansion of cities, construction of condos and hotels on coasts everywhere has grown exponentially. With the invention of the light bulb and therefore artificial light, the sea turtle's natural source of guiding light has been replaced and is no longer the only or the brightest thing of light. With virtually every coast in Mexico now constantly lit with buildings, the hatchlings become easily confused and turned around, few of them making successful treks to the ocean. Studies support artificial light as the leading cause for hatchling disorientation, showing that in 1999, 51% of the nests studied showed signs of confusion with one-fourth of all the hatchlings headed in the wrong direction. Ferrous metal wire mesh screens are commonly used to protect sea turtle nests from predators' excavating and devouring the eggs and hatchlings. A new concern is that nestlings' delicate magnetic sense may not develop normally in the presence of the magnetic field interference from these steel mesh cages. The effects of the use of steel mesh as a cage material may not be known for many years until assessments can be made of the success rate of the first adult populations that developed within such cages begin attempting landfall for nest-making. Gravid turtles or their hatchlings may also be affected by the presence of magnetic fields arising from power cables, iron debris, steel seawalls or other human activities that locally modify earth's magnetic field.