Do Rats Play Dead? What is Tonic Immobility?

Do Rats Play Dead What is Tonic Immobility
Do Rats Play Dead What is Tonic Immobility

Rats have many predators in the wild, including large birds, such as owls, cats, and snakes. These are similar predators of the related opossum, which is known for slumping over and “playing dead” in order to dissuade any larger animal from killing them. 

So, do rats play dead? Yes. Tonic immobility is known as “apparent death” and is used by a range of animals, including sharks, reptiles, and yes, rats, as a fear response or due to pressure on a certain part of their body. It is also known as “feigning death.” 

Read on to learn why rats “feign death,” how tonic immobility works, how to tell if your pet rat is playing dead (and what to do), and other animals that experience the same phenomenon. 

When Do Rats Enter Immobility? 

Rats will enter a state of “apparent death” or reflexive freezing on two occasions: 

Dorsal Immobility 

The first is when rats are picked up by the scruff of their necks. Since mothers transport their young this way, going limp is a reflex young rats carry into adulthood. A limp baby rat is much easier for the mother rat to transport in times of danger than a squirming one, which may be why the reflex exists. This is called “dorsal immobility.” 

Since this reflex still exists in adult rats, picking them up by pinching the nape of the neck will induce limpness. However, this can make a rat feel helpless and fearful. 

The best way to handle a pet rat is to hold them by their midsection and under their lower half. Make sure to never dangle them from a limb or by their tail. This way, the rat is secure and supported. 

If you need a visual demonstration, here’s a video explaining how to pick up and handle your rat:

Tonic Immobility 

The second type of rat immobility is tonic immobility, which is when pressure is applied to a rat’s upper back, typically while lying belly up on the ground, that causes the same type of “freezing” or “playing dead.” 

This “freeze” is related to the “fight or flight,” reflex, which is a human or animal’s reaction to danger. The animal will either fight the predator, run from it, or hold completely still, depending on the circumstances. 

Tonic immobility is a fear reaction, possibly developed to make predators think the animal is dead. Animals do not consciously work this out themselves, rather a combination of position and adrenaline freezes the animal in place. 

Scientists have found that a combination of position and pressure on the back of a rat will put the rat into a trance. The harder the pressure on the rat’s upper back or neck, the longer the trance lasts. However, the length of the trance will also vary from rat to rat.

Additionally, the more fearful or submissive the rat is, the longer the rat will be frozen.

Rats can also put each other in tonic immobility. A more aggressive rat will roll a submissive rat onto its back, which can effectively freeze the rat. 

Another study found that the hypnotized state of the rats meant that their muscle mobility and tone were suppressed, making it so they couldn’t move until the trance was over. The rat’s breathing may also become shallower, while eyes will typically stay open and alert. 

It is important to note that this type of “feigning death” is different than when possums play dead. In that case, the possum is directly trying to dissuade predators from eating them. In the case of rats, tonic immobility can be induced simply with pressure on the neck area, or by a combination of adrenaline and light pressure. 

How to Tell if Your Rat Is “Playing Dead”

If you want to check if your rat is playing dead, use this step-by-step process:

  1. If you see your rat unmoving in its cage, check if your rat’s chest is rising. This would be a signal that the rat is breathing and that their heart is beating. Typically in this state, their eyes will be open. 
  2. Rats will be unresponsive to touch while “playing dead,” so don’t try to shake or poke your rat. Instead, wait until they move. If needed, gently move the rat into a dark, sheltered place to lower your rat’s fearfulness. 
  3. Check to see if anything has startled your rat. Since a rodent’s “hypnosis” is often in correlation to danger, make sure there’s nothing in the area (a larger pet, a bird at the window, etc.) that could be causing a fearful reaction that helps to induce the frozen state. 
  4. Lastly, wait it out. A rat will typically come out of a tonic immobility trance after a few minutes. Be patient, and watch for movement of the limbs that signals the end of their “hypnosis.” 

If your rat continues to not move for over 30 or so minutes, provided they seem to be alive, take them to the vet to get them checked out. 

Other Animals That Play Dead

Rats are not alone in this phenomenon of “feigning death.” Many other animals enter a state of tonic immobility when scared or put in a certain physical position. 

Sharks

Believe it or not, sharks can be put into a trance by being physically restrained upside down. After about a minute, the shark will stop struggling and remain in its back. Since sharks cannot move water through their gills while in this position, they can suffocate to death after about fifteen minutes. 

Predators of sharks, such as orcas, will induce this state of paralysis in order to kill a shark. After ramming into the shark, the orca will flip it and hold it there until suffocation. 

Additionally, aquarium workers will sometimes use tonic immobility (for short periods of time) in order to handle wild sharks safely. 

Since this state of hypnosis is dangerous for a shark, it’s unclear why they have developed to do it. 

Chickens 

To put a chicken in a trance, you can flip it onto its back and stroke its throat. The tonic immobility response in chickens is seen as linked to fear; however, the chicken does not have to be afraid to be put into the trance. 

Additionally, with a chicken’s head parallel to the ground, a chalk line drawn out from their beak can hypnotize them into stillness for ten or fifteen seconds. 

Tonic immobility has also been used to kill chickens more humanely for meat, as the chicken is less likely to struggle and cause more pain to itself during slaughter. 

Snakes and Opossums 

Both opossums and certain types of snakes, like the hog-nosed snake, exhibit a type of tonic immobility called thanatosis, where they specifically play dead when predators are around. Possums will slump, and slow breathing, while the hog-nose snake will emit an odor that smells like, well, a dead snake would. 

Thanatosis is what most people think of when they hear “playing dead.” It is a more deliberate and conscious decision, rather than the feigning death that occurs in rats. 

Conclusion 

Rats are prone to freezing or going limp when pressure is applied to their upper back. This reaction occurs mostly when the rat is in danger, or fearful of a predator about to eat them. 

Rats “play dead” when held by the scruff of their neck, or when placed on their backs with enough pressure. The trance will end in minutes and is not a cause of concern for a pet rat owner. 

While “playing dead” is not fully understood, it is not harmful to your rat. Don’t worry! Just wait it out. 

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