Biologists that work with cave life are known as speleobiologists. Working in caves is challenging and requires carrying equipment into caves that are sometimes hundreds of meters in length. The equipment used in caves needs to be tough because the conditions are often muddy and wet. These biologists study species living in caves, some of these species are only found in caves. The species that are only known from caves are known as troglobites if they live on land and stygobites if they live in water.