Amphibian represents an individual's ability to survive underwater as well as on land. Typically, such an ability requires certain physical requirements such as ectothermic body temperatures and alternative means for oxygenating the blood stream (usually through the use of gills). Those who possess amphibious traits are known to have perfect equilibrium, which enables them to maintain a flawless sense of balance and their body can compensate for dramatic changes in water pressure. Amphibian characters can survive on land, but some may only be able to do so for limited periods of time.