#rex rats

Anyone play roblox?

From a companion animal standpoint, I don’t really see a good reason to deliberately cultivate a population of rats with no tails, or no hair, or curly whiskers, or impaired vision coupled with an impaired sense of smell and/or reduced olfactory response (which some studies suggest might be the case for rats with albinism).

If the goal of breeding is to improve the health of the species overall—which many breeders do claim—then pursuing these varieties feels counterintuitive. You can’t, to the best of my knowledge, breed better eyesight into a rat with albinism, or alternative methods of thermoregulation into a rat with no tail.

Theoretically these things might be possible, many generations down the line, but the likelihood of any pet breeder actually achieving this—let alone in a timely manner, without first producing hundreds or thousands of impaired rats—is slim.

And most, in my experience, aren’t even trying to. Every manx breeder I’ve seen who talks about “improving the health of the variety” speaks as if this task is already complete in their line, and/or leaves thermoregulation out of the equation entirely, and simply assumes that because their manx rats don’t visibly struggle with mobility or show noticeable signs of pain, they must be suffering no ill effects from the fact that they’re missing a huge chunk of the body they evolved to inhabit.

But if we’re trying to be ethical from an ecological standpoint, we have to look at the reality that sometimes pet rats escape (or are released) into the wild, and reproduce. And from there they can destroy crops, invade homes, spread diseases, and out-compete or directly attack native wildlife. These threats are not unique to rats, but should be considered when trying to justify bringing more of them into the world.

Different sources state different litter sizes, with the highest maximum I’ve seen so far being 18 and the lowest maximum being 12. Rats can reach fertility at just a couple months old, sometimes as early as five weeks. Their gestation period is only three weeks, and they can become pregnant almost immediately after giving birth.

(This is not good for them, especially at a young age, just to be clear.)

One ecological measure might be to breed a line of rats that tends towards smaller litter sizes, lower fertility rates, and/or early infertility—if that’s even possible to achieve without other health complications. I have no idea.

Even if it is possible, however, this would inherently complicate every other aspect of the program. Rats’ fertility is one of the things that makes them such an efficient animal to breed. Lowering the litter size by a wide enough margin to make an ecological difference would also drastically reduce the chances of producing the specific traits you’re aiming for.

So it becomes a balancing act of breeding rats who can exist comfortably in a domestic situation, but which would not thrive in the wild.

Part of this concept—that a domesticated animal does not need the same traits as their wild counterparts—has been put forward to justify the breeding of manx rats. I have already explained at length why I do not believe manx rats’ impairments can be adequately accommodated in even the cushiest pet home. Tumblr hates links, but it’s the first post on this blog.

So where is the line drawn?

Let’s look at Alaska. Only one variety of Norway rat is allowed in Alaska: PEWs. Albino rats, aka Pink-Eyed Whites.

PEWs have worse eyesight than the average rat, may have a reduced sense of smell and/or reduced olfactory response, and are—as the name suggests—white. All of this in combination makes them easier to spot and catch, whether they’re being pursued by a predator or a human.

I am having trouble finding any sources that confirm this is why only PEWs are allowed, but this has been discussed frequently in rat circles. I might question how effective this is in the snowier regions, where a white animal would presumably have an easier time blending in, but I could be wrong about that.

Either way, I am just using Alaska as an example. In addition to the statewide PEW-only rule, some places—such as Anchorage—ban pet rats altogether.

So, does this work? I can’t say for sure, but an article posted on the Alaska Department of Fish and Game's website in December of 2020 states that Anchorage "may be the largest rat-free port in the Northern Hemisphere." (Source will be linked in a reblog.)

If we say, for the sake of argument, that it does work, and if this were implemented on a wider scale, is the quality of life tradeoff acceptable?

I don’t know.

The coat color making the rats more visible to predators, yes, absolutely. A pet rat (being kept responsibly) does not need to blend into its surroundings, and should not be affected by this in any way.

Rats don’t seem to rely on their eyes very much in the first place, so I am not overly concerned with that aspect, either. Or I wouldn’t be, if it wasn’t potentially coupled with a reduced sense of smell and/or reduced olfactory response. I have not yet read the studies that suggest this, which is why I keep referring to it as a hypothetical, but those studies were quoted in a source that I generally trust.

Sense of smell is extremely important to rats, and the results of those studies suggest a vast difference in rats with albinism.

Interestingly, one of those differences might directly affect reproduction rates amongst rats who survive long enough to reproduce in the first place:

Quote from "The rat's world of smell" by Anne Hanson on RatBehavior dot org. (Source will be linked in a reblog.)

Sachs (1996) tested male albino and pigmented rats' response to the remote cues of a female rat in heat. Sachs used a testing chamber that was divided in half by two wire mesh screens separated by a few centimeters, so the male rat on one side could see and smell a female in heat on the other side but could not touch her. Sachs found that 83% of pigmented male rats became aroused, but only 4% of albino rats did.

This could potentially curb escapee reproduction rates without affecting a breeding program, if the lack of arousal only indicates that the albino rats were having trouble detecting the females. A rat who is able and willing to reproduce when offered the chance, but who cannot easily find a mate in the wild, could be what we are looking for.

But the question of QOL remains. I can’t say for certain whether a pet rat is impacted by an impaired sense of smell on a level that makes their production unethical, if that is indeed true of PEWs. I can say I would be fighting a losing battle on multiple fronts if I did take that stance. I am also unsure how albinism might impact a (non-hairless) rat’s risk of sunburn, and whether light actually hurts their eyes.

Rex rats are another case where I’m on the fence. Perhaps a rat who lives in a nice cage in a climate-controlled room, where all of his needs are fulfilled and there are no active dangers to detect, will never actually suffer (beyond mild inconvenience) for his reduced field of whisker “visibility,” or his lack of fur.

But this case raises questions in the other direction. Is a rex rat meaningfully less able to thrive in the wild than a non-rex rat? How much of a difference do shorter, curlier, fewer whiskers make when being stalked from afar by a bird of prey? I don’t know.

Rexes with bald patches, or who lack fur entirely, would be more prone to both sunburn and low temperatures. But how much does that matter, in terms of pest control? A sunburned rat can still chew through plastic or dig up crops. A cold rat may be even more determined to find its way into a heated garage.

I might hesitantly propose a less stringent version of the current Alaska rule. One that imposes restrictions on coat color, depending on regional camouflage options, but doesn’t require albinism. However, this lacks the potential reproductive stumbling block of the PEWs, as well as their potentially reduced ability to smell predators.

I absolutely love these rats, they sleep in the silliest positions and you can tell they're really bonded

Also has anybody had rats that would groom another rat while on their back? Like when rat 1 has rat 2 pinned and is grooming them, but in this case rat 2 is grooming rat 1 at the same time