To take on form we expend energy or lifeforce. The astral vampyre can't create body heat and stay in the metaphysical sate for long. Therefore we feel like the icy hand of death to a body when we enter. If we warm up to our surroundings first then there is little difference in temperature. Vampyre females are generally programmed to give lifeforce energy to nuture their children. Therefore they may have a hard time keeping warm in a body and need a heat source. Males generally draw down force to defend and build lifeforce which is used for keeping the body warm and generating heat. In times past females had to hide their energy patterns like a fawn that carries almost no scent. Males irradiated heat to draw hunters after them. That is why many think there are mostly male vampyre. Even in the body a female vampyre gives off little scent. Its hard for a hunter to even recognize them. But a male blood vampyre knows exactly what they are looking for and will recognize them by mind contact if nothing else.