Rat tails have a thermoregulatory function; meaning, a rat's tail is involved in the loss of heat. As opposed to the rest of the rat body, the tail has no fur and has a large surface-to-volume ratio. Replete with blood vessels (especially at the tip of the tail and mid-length), the rat tail helps rats dissipate about 17 percent of their heat.
Rats modify their body temperature by either dilating or constricting their tail's blood vessels.
When a rat's temperature rises, its tail's blood vessels expand, allowing for the flow of warm blood to the tail. This happens in a process called vasodilation. When a rat's temperature drops, its tail's blood vessels shrink in diameter in a process called vasoconstriction, reducing blood flow to the tail. This reduction in blood flow allows for the cooling of the entire rat body.
So, what happens to a tailless rat? Yes, such rats exist, mutations such as mutations in tail-anomaly lethal (Tal) and stub (st) are causes for a rat to be tailless. Tailless rats do not lose heat, as well as rats with tails are able to. A rat without a tail has a higher core body temperature. Additionally, it takes longer for their high temperatures to come down.
Do you know if rats that have adapted to colder climates generally have shorter tails (to conserve heat) than rats that live in warmer climates?
ReplyDeleteHi Sid! Yes you are absolutely correct. Rats are endotherms, meaning they maintain their bodies at a metabolically favorable temperature. They use the heat set free by their internal bodily functions rather than relying on ambient heat to thermoregulate. Therefore, rats follow Allen's rule.
DeleteAllen's rule (as applied to rats) is that the body shapes and proportions of rats vary by climatic temperature by minimizing their exposed surface area to minimize heat loss in cold climates or by maximizing exposed surface area to maximize heat loss in hot climates. The rule predicts that a rat from a hot climate should have a long and thin tail, as you said. Thanks for your question!
Hi Rohini,
ReplyDeleteThis research sounds so exciting, but I'm less concerned about rats, and more concerned about humans obviously. So could you go more into how your research could apply to human research? Thanks
Hi Sam,
DeleteThanks for reading! Have you ever gotten frightened at a scary movie and moved over to a corner so that nothing scary could come at you from behind? You'll notice that rats have the same tendency - they prefer to be by corners and walls. Just as humans often have their beds against a wall or corner of the room, rats do as well. Humans and rats share many of the same characteristics. Many of our behaviors are actually more common with rats than they are with cats and dogs!
The research I'm conducting aims to look at two structures of the brain: the bed nucleus stria terminalis (part of the limbic system) and the preoptic area (part of the hypothalamus). We are trying to identify the functions of these two areas of the brain within the rat brain because of the implications they have in human brains. For example, in my "Week One" post, I define the BNST and the POA and talk about their roles and functions within the human brain. Due to the similarities in rats and humans behavior-wise, understanding the role and function of the bed nucleus stria terminalis and the pre-optic area can inform researchers about how humans thermoregulate (regulate their body's temperature via internal processes). This information is critical in understanding how humans respond when faced with extreme temperatures, such as we do here in Arizona! Understanding the function of the BNST and POA can help us identify treatments for patients exposed to extreme temperatures, possibly for those with hypothermia or hyperthermia (heat exhaustion).
Will my rat have trouble regulating his body temperature if his tail has grown kinked? My rat has several kinks in his tail that seemed to have become more visible as he is growing (I got him with his eyes closed abandoned by his mother). Why is his tail like this? Is it a genetic mutation or was he maybe dropped or harmed when I found him.
ReplyDelete