Spiders are amazing creatures that can live for quite a long time if conditions are right. But eventually, even the heartiest spider reaches the end of its natural lifespan. In this blog post, we’ll look at how spiders die naturally.
How Do Spiders Die Naturally?
Spiders, like all living things, eventually die of old age. The lifespan of a spider can vary quite a bit depending on the species. Some spiders may only live for a year, while others can survive up to 25 years in the wild!
Most spider species can live for 2-5 years on average if conditions are ideal, and they can avoid predators and accidents. Large tarantulas and bird-eating spiders have the longest lifespans, up to 25 years. Smaller spiders, like jumping and orb weavers, often only make it 1-2 years.
So, what happens inside a spider’s body when it dies of old age? As spiders (and all living things) age, their cells and organs slowly deteriorate. Their digestive system and ability to process food decreases. Their muscles and joints stiffen and weaken. Reflexes and coordination start to suffer. Senses like vision and touch fade.
Eventually, one or more vital organs lose function, leading to a systemic shutdown. The ageing heart has trouble circulating blood and oxygen, leading to organ failure. The worn-out nervous system starts misfiring. Hormone regulation gets disrupted.
Without the proper nutrients, metabolism grinds to a halt. The spider becomes too weak to move or feed itself. After a period of decline, the spider’s bodily functions cease, and it dies. The lifespan countdown hits zero.
Very few spiders die of “old age” before reaching maturity, as they tend to be killed by predators or accidents first. But once they mature, they start the slow march towards their expiration date.
Do Spiders Ever Die of Disease or Illness?
While less common than simple old age, spiders can and do die from diseases, infections and parasites in the wild. Here are some of the more common non-age-related causes of death:
- Bacterial infections – Bacteria that infect a spider’s hemolymph (blood) can lead to septicemia that poisons the internal organs. Often, these infections start as wounds from combat or accidents.
- Fungal growth – Fungal spores and moulds can take hold in the moist book lungs or other areas and weaken or kill a spider.
- Parasites – Parasitic worms and other organisms can infest a spider’s organs and gradually drain away resources. Parasites may enter through prey or transmitted by other insects.
- Dehydration – Spiders can’t properly circulate nutrients without enough water, and their organs fail. This often happens in old age as they lose the motivation to hydrate properly.
- Starvation – Malnutrition and starvation due to lost hunting skills or limited food sources will kill a spider. Digestive system failure results.
- Toxins & poisons – Ingestion of toxins from insecticides or prey can poison a spider’s nervous system and other organs, much like any animal.
Disease doesn’t take down spiders as often as old age. Illnesses and infections are still a significant risk, especially for older spiders with declining health and unlucky younger ones exposed to toxins or parasites. Proper nutrition, hydration and avoidance of toxins keep them healthy.
Do Spiders Ever Die from Physical Injury or Trauma?
Absolutely. For many spiders, injury or trauma is the ultimate cause of death before old age gets them.
Spiders lead hazardous lives and face many threats and dangers daily. Spiders are vulnerable in many ways, from predators trying to eat them to environmental hazards to mistakes during hunting and navigation.
Here are some of the more common physical threats and injuries that can kill a spider:
- Getting eaten or killed by predators like birds, lizards, or other spiders.
- Drowning in bodies of water or floods, as not all spiders can swim.
- Falling from great heights while ballooning or rappelling.
- Becoming trapped in pooled water, chemicals or other hazards.
- Losing legs or palps is critical for movement, sensing or feeding.
- Rupturing their abdomen from falls or attempted escapes.
- Breaking fangs or mouthparts needed for injecting venom or eating.
- Damage to multiple legs from accidents or failed attacks.
- Losing large areas of their protective outer “skin” or exoskeleton.
- Destruction of major sensory organs like eyes or touch receptors.
Unless the injury is very minor, most traumatic physical damage results in a cascade of complications that eventually kill the spider. They may die instantly from massive trauma, like a severe fall. Or linger for days or weeks after an injury before the damage leads to infection, starvation or vital organ failure.
Natural ageing brings about their eventual demise. The hazards and dangers of daily life in the wild cut many spiders’ lives short. Surviving each day is a challenge for spiders, and injury can strike anytime.
Are There Any Other Natural Causes of Death for Spiders?
A few less common natural causes of death for spiders include:
- Moulting issues – All spiders moult their outer exoskeleton periodically to grow. Issues with the moulting process can leave them vulnerable or cause loss of limbs.
- Temperature extremes – Some species of spiders are very sensitive to temperature. Exposure to excessive heat or cold can quickly kill them.
- Cannibalism – Some spiders kill and consume injured or weaker members of their own species when they are very hungry.
- Failed mating – In some spider species, mating results in the male being killed and consumed by the female. Not great for the male!
- Egg binding – Female spiders dying from issues laying their egg sacs is rare but can happen.
What Happens When a Spider Dies?
When a spider’s time runs out, the process of dying begins. Let’s look at this stage by stage:
1. Slowing Down
In their final days, very old spiders begin to slow down. They may stop building webs or cease foraging for food. Their metabolism slows as death approaches.
2. No Longer Moving
Once a spider stops moving entirely, it’s a sign the end is near. They enter a comatose state, no longer reactive to stimuli around them. Their legs curl up beneath them as they slip away.
3. Drying Out
With no new moisture entering their bodies, spiders dry out once deceased. Their abdomens shrivel and harden. Many spiders assume a classic death pose with legs curled beneath them as rigour mortis sets in.
4. Decay Sets In
Once dead, decay starts breaking down the spider’s tissues. Enzymes and microbes within the spider’s body begin decomposition. Other insects may also feed on the dead spider’s remains in the wild.
In most cases, the spider’s soft tissues disappear entirely within several weeks, leaving only a dried exoskeleton behind.
Do Male and Female Spiders Tend to Live the Same Length of Time?
An interesting fact about spiders is that males and females often have quite different average lifespans. There are a few key reasons for this difference:
- Mating risks – In some species, the mating process is very dangerous for the males as they risk being killed and eaten by the females.
- Post-mating death – Male spiders often die naturally within 1-2 months after mating, essentially dying from their efforts to reproduce.
- No parental care – Male spiders provide no parental care and die off after mating, while females live to birth and care for offspring.
- Roving lifestyle – Males often have a riskier lifestyle of roaming and searching for mates, facing more threats.
- Larger size of females – The larger body size of female spiders requires more time to reach maturity and allows them to live longer.
In many common spider species, the female lifespan is 2-4 times longer than the male on average. Females may live 2-3 years, while males of the same species live only several months or a year at most in some cases.
However, in some species where mating risks are fewer, and males continue hunting after mating, the male lifespan is closer to females. Overall, though, the reproductive strategies of most spiders lend towards shorter lifespans for males compared to females of the same species in the wild.
Do Spiders Show Signs of Aging as They Get Older?
Spiders do exhibit some clear signs of ageing and reduced vitality as they reach old age, similar to other animals:
- Slower movement – Older spiders move more slowly and have difficulty running, jumping or climbing due to muscle weakness and stiff joints.
- Cloudy eyes – Many old spiders have significant cataracts and cloudiness in their eyes due to protein buildup, reducing hunting ability.
- Balding/hair loss – Older individuals may have patches of lost body hair and appear scruffy or balding.
- Dulled colours – Bright skin pigments and patterns often fade significantly in ageing spiders.
- Leg dragging – Older spiders sometimes drag legs that don’t move properly due to age-related nerve issues.
- Poor traction – Grip strength in leg pads declines with age, causing slips and falls.
- Loss of appetite – Many old spiders show minimal interest in eating prey, leading to weight loss.
- Lethargy – Elderly spiders spend more time resting quietly rather than actively hunting and web building.
- Leg curling – Older spiders sometimes have legs curled in unnatural positions due to muscle and joint stiffness.
In their elder years, it certainly becomes more challenging for spiders to capture food, build webs, reproduce and avoid predators. But their sedentary lifestyles mean that some can eke out their final days relatively safely before their aged body gives out completely.
Do Spiders Try to Avoid Dying by Hiding When They Get Old?
It seems that some types of spiders do exhibit behaviour indicating they “know” when death is approaching and try to hide away more. Here are some signs very old spiders are preparing for death:
- Spending more time hidden in shelters and dens rather than exposed.
- Sealing themselves off more securely in silk retreats and burrows.
- Curling up tightly in dark corner spots that feel safer.
- Moving much more slowly and cautiously to avoid threats.
- Staying put in web hideaways rather than roaming around.
- Building egg sacs for the final brood before dying.
- Not actively preying on food even when very skinny.
- Shying away from any disturbances or explorations.
- Letting legs curl under the body rather than using strength to extend them.
So, while anthropomorphizing animal behaviour can be inaccurate, old and dying spiders appear to seek more cover and avoid risks in their final days and weeks. They seem to “know” at an instinctual level that death is approaching, even if they don’t comprehend it cognitively.
By staying hidden and conserving resources, elderly spiders may eke out just a little bit more life while protecting themselves from threats. But eventually, their time still runs out no matter how safely they hole up.
Do Some Spider Species Practice Matriphagy or Self-Cannibalism?
Matriphagy is an extreme example of spiders not dying naturally of old age – it’s when spider mothers allow their young to eat them alive! This only occurs in about 20-25 out of some 48,000 total spider species, so it’s quite rare.
In these matriphagal species, the mother spider willingly sacrifices herself as a final meal to provide nutrients for her spiderlings as they start life independent of her care. Some specific examples include:
- Dark fishing spiders
- Protective wheel spiders
- Forest wolf spiders
- Australian crab spiders
- Certain tunnel-web spiders
This nutritious “parting gift” from mom gives her babies the strength for dispersal and finding their own prey. This allows them to survive and avoid cannibalizing each other instead.
Matriphagy demonstrates amazing spider maternal care and devotion. The mothers could run away but instead, give their lives to provide for the next generation. While cruel sounding, it causes little pain for the mother as her offspring’s small bites gradually consume her from the feet up. What a way to go!
Do Spiders Always Die On Their Backs?
A common myth states that spiders die by curling up on their backs. Is there any truth to this?
In short – no. While some spiders may end up dorsal side up when dying, this isn’t a hard rule. Let’s explore why this misconception came about:
- Dying spiders do tend to draw their legs in under their bodies. This can sometimes flip them over onto their backs.
- Spider rigour mortis may set in with the legs curled, creating a dead spider in a “supine” position.
- In lab studies, freshly killed spiders may be placed abdomen up to view anatomical features. This created an incorrect assumption that dying spiders inherently flip over.
Spiders die in various positions and postures depending on species and circumstances. Some may remain on their front or sides instead of their backs.
Certain species like tarantulas have been observed dying curled into a ball rather than legs splayed out. There’s no guaranteed pose for a dying spider!
The next time you encounter a deceased spider, know there’s no single way they meet their end. The process varies across the 40,000 diverse spider species on our planet.