An illuminable device configured to be worn by a mammal and provide visibility to the mammal includes a thermoelectric module and a light source. The illuminable device is configured to be mounted onto a mammal by an article worn by the mammal such that the thermoelectric module is in thermal contact with the mammal's body. The thermoelectric module generates electricity from a thermal gradient, produced from a mammal's body heat that is transferred to the module. The electricity generated by the thermoelectric module powers the light source to illuminate the article worn by the mammal. Related methods are also provided.