Aging is a fact of life: We watch our parents, pets and selves age along with non-living things like cars, clothes and outdated iPhones. Immortality is something we don’t accept as real, but what about the crocodile? Does it disprove or challenge our beliefs around everlasting life? Yes, thanks to their “negligible senescence.” Senescence is biological aging: things like losing the ability to reproduce or losing functions necessary for life due to aging. Senescence, or aging, defines a species’ lifespan. Crocodiles may exhibit negligible senescence: no deterioration due to aging. This means that Instead of an average or defined lifespan, they are more likely to die due to accidents, disease, predation or starvation. Does that make them immortal? It depends how you look at it.