The SVL can change depending on whether the animal is alive, dead, moving, or still. It can change if scientists have used chemicals to stop its dead body from rotting. Scientists also use snout-vent length on fossils. With fossils, they use osteological correlate, which is a way the bone can match the rest of the body. Precaudal length is one osteological correlate. A scientist can look at the animal's SVL, weight, and body and may be able to tell if it is male or female or how old it is.