Deer kick after death due to residual electrical activity in their muscles and nerves, even after the brain has stopped functioning. This phenomenon, along with the onset of rigor mortis, is a natural part of the post-mortem process, and understanding it can help hunters manage and process their game more effectively.

In this article, we’ll give a detailed breakdown of everything you need to know about why deer kick after death, including research-backed answers and actionable advice you can implement to improve your meat quality.

Note: This is the start of our broader series on how to improve the meat quality of your hunted deer. Feel free to browse the “Hunting” category to discover the rest of the series.

Below is a deer Rigor Mortis and Cooling Rate Calculator you can use as a guide for handling your deer meat. It’s only a guide, but the key is to get the deer’s core body temperature below that golden 40°F (4°C) temperature as quickly as possible.

The Biological Processes After a Deer’s Death

When a deer dies, it’s not like flipping off a light switch. The body goes through a complex series of changes that can take hours or even days to complete.

The Immediate Effects of Death on a Deer’s Body

Right after the heart stops, the body enters a state of primary flaccidity. All muscles relax completely. This is why you might see a deer collapse instantly when shot through the heart or brain. But here’s where it gets interesting:

“Recent studies have shown that even after clinical death, cells can remain active for up to 48 hours, with some genes increasing their activity post-mortem.” – 2021 study in Nature Communications

This cellular activity can contribute to some of the puzzling post-mortem movements we see. But it’s not just about movement. The body begins to cool (algor mortis), blood starts to pool in the lowest parts of the body (livor mortis), and the internal organs begin to break down.

The cooling process is particularly important for hunters to understand. A deer’s body temperature is normally around 101°F (38°C). After death, it will cool at a rate of about 1.5°F (0.83°C) per hour, depending on environmental conditions. This cooling affects everything from meat quality to the onset of rigor mortis.

The Onset of Rigor Mortis in Deer

Rigor mortis, the stiffening of muscles after death, starts when the deer’s temperature starts to change, usually anywhere from 1-4 hours in deer. But get this:

“Environmental temperature significantly affects the onset of rigor mortis. A 2018 study in the Journal of Forensic Sciences found that for every 18°F (10°C) increase in ambient temperature, the onset of rigor mortis accelerated by approximately 1 hour.”

This means on a hot day, that deer you shot might stiffen up a lot faster than you’d expect. But it’s not just about temperature. The pH level in the muscles also plays a crucial role.

When a deer is alive, its muscle pH is around 7.2. After death, lactic acid builds up, causing the pH to drop. When it reaches about 5.7, that’s when rigor mortis kicks in full force. This pH drop is why meat from stressed animals (like those chased by dogs or injured animals) can be tougher – they’ve burned through their glycogen stores, leading to a more rapid pH drop and earlier onset of rigor mortis.

Why Do Deer Kick After Death?

Now, let’s get to the heart of the matter. Why do deer kick after death?

Understanding Post-Mortem Muscle Spasms

These kicks aren’t your deer coming back to life. They’re caused by residual electrical activity in the muscles and nerves. Here’s a mind-blower for you:

“A 2020 study revealed that certain genes related to stress response and inflammation actually increase their activity levels up to 24 hours after death.”

This ongoing cellular activity could contribute to these post-mortem movements. But it’s not just random twitches. Sometimes, you’ll see coordinated movements that look almost lifelike. This is because the spinal cord can still send signals to muscle groups even after the brain has stopped functioning.

These movements can be triggered by a variety of factors:

1. Buildup of lactic acid in the muscles
2. Release of stored calcium ions in the muscle fibers
3. Nerve endings firing spontaneously as they die off
4. Changes in air temperature or barometric pressure

The Role of the Nervous System in Post-Mortem Movements

Even after the brain stops functioning, the spinal cord can still fire off signals. It’s like a computer with a bad motherboard – some parts are still trying to work.

The nervous system is complex, with three main parts:

1. Central Nervous System (brain and spinal cord)
2. Peripheral Nervous System (nerves throughout the body)
3. Autonomic Nervous System (controls involuntary functions)

After death, the brain quickly stops functioning due to lack of oxygen. However, the spinal cord and peripheral nerves can remain active for some time. This is why you might see movements concentrated in the limbs or tail, rather than coordinated whole-body movements.

The autonomic nervous system is particularly interesting in this context. It controls things like heart rate, digestion, and reflexes. Some reflexes, like the knee-jerk reflex, are controlled entirely by the spinal cord without input from the brain. This means they can potentially still function briefly after death.

I’ve seen my fair share of post-mortem deer kicks (and bruised shins to go with it). 

Rigor Mortis: The Stages and Their Significance

Rigor mortis isn’t just about stiff muscles. It’s a complex process that goes through several stages.

The Chemical Process Behind Rigor Mortis

When a deer dies, its body stops producing adenosine triphosphate (ATP). Without ATP, muscle fibers can’t relax after contracting. 

“A 2019 study in the Journal of Animal Science found that the rate of ATP depletion in muscle tissue post-mortem can vary by up to 30% between individual animals of the same species, potentially explaining variations in the onset of rigor mortis.”

This ATP depletion is just the start. As ATP levels fall, calcium ions flood into the muscle fibers. These calcium ions cause the actin and myosin filaments in the muscles to link up, creating the stiffness we associate with rigor mortis.

The process happens in stages:

1. Pre-rigor: Muscles are still soft and pliable
2. Onset of rigor: Muscles begin to stiffen
3. Full rigor: Maximum stiffness is reached
4. Resolution of rigor: Muscles begin to soften again as proteins break down

Factors Influencing the Onset and Duration of Rigor Mortis

Several factors affect how quickly rigor mortis sets in and how long it lasts:

1. Temperature: Warmer temps speed up the process. In hot weather, rigor mortis can set in as quickly as 20 minutes after death.
2. Animal size: Bigger deer take longer to cool, affecting rigor mortis timing. A large buck might not enter full rigor for 12 hours, while a small doe could be stiff in 3-4 hours.
3. Physical activity before death: A deer that was running hard will have less ATP in its muscles, potentially speeding up the onset of rigor mortis.
4. Age: Younger animals tend to enter rigor mortis faster due to higher metabolic rates and more glycogen in their muscles.
5. Muscle type: Different muscle groups enter rigor at different rates. Generally, smaller muscles (like those in the face) stiffen first, while larger muscles (like those in the legs) take longer.
6. Health of the animal: Diseased or malnourished animals may experience altered rigor mortis patterns due to differences in muscle chemistry.

How Rigor Mortis Affects Meat Quality and Preparation

Here’s something every hunter should know: how you handle a deer during rigor mortis can make or break your venison quality.

“Research showed that meat processed during peak rigor mortis can be considerably tougher than meat processed either before or after this stage.” As someone who opened his own venison deli, I can attest to this study. After I hunted my animals I would let the carcasses hang for at least 3 days (preferabbly 5-7 days) in a 39.2°F (4°C) cool room. 

This is why many experienced hunters prefer to let their deer “age” for a day or two before processing. As rigor mortis resolves, natural enzymes in the meat begin to break down tough muscle fibers, resulting in more tender meat.

However, you can’t just leave your deer hanging indefinitely. After about 24-48 hours (depending on temperature), bacterial growth becomes a concern. This is why proper cooling is crucial, hence my 39.2°F (4°C) cool room. 

Some hunters swear by techniques like hot-boning (removing meat before rigor sets in) or cold-shortening (rapidly chilling the carcass). Both methods can affect meat tenderness, but they require careful timing and temperature control. 

Implications for Hunters and Field Processing

Now, let’s talk practical application. How does all this sciency stuff affect us in the field?

Safety Precautions for Hunters

Always approach a downed deer with caution. Those post-mortem kicks can be powerful enough to cause injury. I always tell new hunters to approach from behind the deer’s head and to keep their distance until they’re absolutely sure it’s dead.

Here are some safety tips:

1. Approach from behind the head, staying out of range of the legs.
2. Look for signs of life: eye movement, breathing, or muscle twitches.
3. Poke the eye with a long stick. If there’s no blink reflex, it’s likely dead.
4. If you must get close, stay alert and be ready to move quickly.

Remember, a wounded deer can be dangerous. Even if you’re sure your shot was fatal, treat every downed animal as if it could suddenly jump up.

Assessing Time of Death and Field Dressing

You can use the stages of rigor mortis to estimate how long a deer’s been dead:

1. 0-3 hours: Body is limp
2. 3-12 hours: Stiffening progresses
3. 12-24 hours: Full rigor mortis
4. 24-48 hours: Rigor mortis starts to pass

This can be useful if you’re tracking a deer you shot earlier or if you’ve found a deer someone else shot. However, remember that these timeframes can vary based on the factors we discussed earlier.

When it comes to field dressing, timing can be crucial. If possible, it’s best to dress the deer before rigor mortis sets in fully. This makes the process easier and can help cool the meat faster. If the deer is already stiff, you might have a tougher time, especially with tasks like removing the hide.

Here’s a pro tip: if you’re dealing with a deer in full rigor, try to work with the stiffness rather than against it. For example, propping the deer’s legs out to the sides can make it easier to access the body cavity.

Practical Considerations for Transporting and Storing Deer

If possible, transport your deer before rigor mortis sets in fully. If you can’t, be prepared for a stiff, awkward load. A deer in full rigor doesn’t bend easily, which can make loading it into a truck or game cart challenging.

When storing, try to position the deer how you want it before rigor sets in. It’ll make your life easier later. If you’re hanging the deer, try to get it into position quickly. Once rigor sets in, it can be difficult to reposition without damaging the meat.

Cooling is critical. If temperatures are above 40°F (4°C), you’ll need to ice the carcass or get it into a cooler quickly to prevent spoilage. Some hunters use a technique called the “plastic bag method” where they fill the body cavity with ice and seal it with a plastic bag. This can buy you some time if you can’t process the deer immediately.

Remember, the goal is to get the internal temperature of the meat down to below 40°F as quickly as possible. This slows bacterial growth and helps prevent spoilage.

Debunking Myths and Misconceptions About Deer After Death

There’s a lot of hogwash out there about deer “coming back to life” or having supernatural post-death movements. Let’s set the record straight.

Common Misunderstandings About Post-Mortem Movements

I’ve heard hunters swear their deer was “playing possum.” The truth is, it’s all just normal post-mortem processes. Understanding this can prevent dangerous practices in the field.

Some common myths include:

1. “If it kicks, it’s still alive”: Not necessarily. Post-mortem kicks can be very strong.
2. “A deer’s heart beats for minutes after death”: The heart may twitch, but it’s not beating in any functional way.
3. “Deer feel pain after being shot”: Once the brain is deprived of oxygen, pain sensation ceases.
4. “You can revive a recently dead deer”: Once true death occurs, there’s no coming back.

Related Phenomena: Other Animals and Their Post-Mortem Movements

Deer aren’t the only critters that do the post-mortem dance. This phenomenon is observed across the animal kingdom.

Comparing Post-Mortem Movements Across Species

From fish flopping in the cooler to chickens running around with their heads cut off, post-mortem movements are common in many species. Each animal has its quirks, but the underlying processes are similar.

Some interesting examples:

1. Chickens: The famous headless chicken phenomenon is due to the location of the brain stem, which can keep the body moving even after decapitation.
2. Snakes: Can continue to move and even strike for hours after death due to their slower metabolisms. It’s one of the main reasons why this article on “are snakes still venoumous after they die”is so important to read. 
3. Fish: Often continue to flop and twitch due to the high concentration of white muscle fibers, which can contract even with low oxygen levels.
4. Frogs: Frog legs are known to twitch when salted, even long after death, due to the sodium ions triggering muscle contractions.

In mammals like deer, post-mortem movements are generally less dramatic than in these examples, but they can still be quite noticeable.

The Impact of Post-Mortem Phenomena on Wildlife Research

Scientists study these post-mortem movements to learn more about animal physiology. This research isn’t just academic – it’s helping develop better practices for wildlife conservation and management.

For wildlife managers, understanding post-mortem processes can help in several ways:

1. Estimating time of death in poaching cases
2. Understanding how different hunting methods affect meat quality
3. Developing better protocols for humane culling when necessary
4. Improving our understanding of how environmental factors affect wildlife populations

Quiz Time! Deer Kick After Death

Key Takeaways – Deer Kick After Death

1. Post-Mortem Movements Are Normal: The kicking and twitching seen in deer after death are due to residual electrical activity in the muscles and nerves, not signs of life.
2. Rigor Mortis Timing Varies: Rigor mortis typically begins 1-4 hours after death, but factors like temperature, animal size, and physical activity can affect the timing.
3. Temperature Impacts Rigor Mortis: Warmer temperatures speed up the onset of rigor mortis, with every 18°F (10°C) increase accelerating the process by about one hour.
4. Handling Deer During Rigor Mortis Affects Meat Quality: Processing deer meat during peak rigor mortis can result in tougher meat. Aging the deer for 1-2 days can help tenderize the meat.
5. Safety First: Always approach a downed deer with caution. Post-mortem kicks can be powerful, so ensure the animal is fully deceased before getting close.
6. Cooling is Crucial: To preserve meat quality and prevent spoilage, cool the carcass quickly to below 40°F (4°C) using ice or a cool room.
7. Debunking Myths: Post-mortem movements are purely physiological. Understanding them helps prevent dangerous practices and improves field processing techniques.