Spiders waving at humans is a phenomenon that many people have claimed to experience but do not fully understand. When a spider raises one or more of its legs and moves them back and forth in your direction, it can certainly look like the spider is waving hello! But is this truly the spider’s intent? Or is there another explanation for this behavior? In this article, we will explore the possible reasons spiders wave their legs at humans and examine the evidence behind each theory. Discover the curious science and behavior behind spider waving!
Do spiders have vision good enough to see humans waving?
Spiders have complex eyes, but their vision is very different from human sight. Most spiders have eight eyes arranged in various patterns on their heads. Some key facts about spider vision:
- Spider eyes are simple (they do not see detailed images)
- Their main focus is detecting movement
- Most spiders only see a few feet away clearly
- Jumping spiders have excellent vision for hunting
- Web-building spiders rely more on vibration senses from their webs
So could a spider spot a human waving and know to wave back? Perhaps not. While spiders can detect large moving objects, their poor visual acuity makes it unlikely they could distinguish a clear human shape at any distance or recognize waving. Jumping spiders probably have the best chance of seeing human motions. But for most spiders, their vision seems too rudimentary to intentionally wave at us.
Are spiders smart enough to understand waving?
Spiders have tiny brains, so they operate mostly on instinct rather than higher intelligence. Their brains lack advanced processing power for learning, emotion, and socialization. While spiders exhibit complex behaviors for web building, navigation, courtship, and hunting, most of this is driven by innate behaviors and responses. They are not known to have the capacity for social signaling, communication, or purposeful interactions with other species. It’s improbable that spiders have the intelligence to consciously understand the meaning of waving gestures. Their small brains likely prevent them from intentional, cross-species communication through waving.
Why spiders wave their legs
If spiders can’t really see us or understand waving, why does it look like they wave at humans? Spider leg waving likely stems from these key factors:
1. Spiders use leg motions to sense vibrations
A spider’s legs are covered in sensitive hairs that detect even minute vibrations. These hairs allow spiders to feel prey movement in their webs or on the ground. Leg waving and motions may act as a way to increase their tactile sensing of surroundings. The leg waves pick up vibrations, air currents, and other environmental information to the spider. So some leg waving is likely just a spider gathering sensory info about a large approaching object like a human.
2. Waving can be a defense behavior
Many spiders employ “deimatic displays” as a defense tactic. Deimatic means to startle or intimidate. When threatened, spiders may wave legs, lift their front pairs of legs, rock their bodies, or make erratic motions. These exaggerated movements try to confuse predators or make the spider look scarier. So some spider leg waving aimed at humans may be defensive posturing if they perceive you as a threat.
3. Spiders prepare for potential attack
Waving the first set of legs may also prepare spiders for attack if needed. The front legs contain the fangs and venom, so raising and extending these primes them for defensive biting. If the spider decides not to bite, it can smoothly lower itself and retreat if given the chance. So spider leg waving allows them to both assess threats and get ready to strike.
4. It is a display of aggression
Male and female spiders wave legs during courtship and mating rituals. But leg motions also signal aggression and intent to attack in disputes over food, territory, or mates. The waves communicate a willingness to strike. So when aimed at humans, spiders may be indicating aggression and trying to scare us off.
5. Spiders may mistake swatting for prey
Rapid human hand motions like swatting can fool spiders into thinking an insect just flew by. Their attack instincts kick in, making them quickly grab at the motion with their front legs. So spiders may wave legs at humans in futile attempts to catch the “prey” they think they see when we swat around them.
Do spiders ever intentionally wave at humans?
While likely rare, some jumping spiders and other highly visual species may be capable of waving at humans on purpose:
- Jumping spiders have excellent vision and can follow human motions.
- Intelligent spiders like Portia may have the brainpower to recognize humans.
- Captive tarantulas and other handled spiders grow used to their owners.
- Repeated exposure to waving humans could allow spiders to associate the gesture.
But these would remain isolated incidents not representing most spider behavior. Limited learning and social skills make purposeful communication with humans quite difficult for spiders. Overall the evidence argues strongly that spider leg waving and motions aimed at humans are not true waving but rather instinctual behaviors spiders naturally perform to interact with their environment and other creatures.
Do spiders wave at each other?
While not waving per se, spiders do use leg motions and body positions to signal and communicate with each other:
- Leg tapping indicates a spider’s intent to mate.
- Leg wavings and zigs-zags are seen in spider courtship dances.
- Male spiders display aggressive leg waving to defend mates.
- Spiders make deimatic postures to defend territory.
- Spiders signal their mood and intent with body stance (crouched = aggression, lifted = submission).
These leg and body motions convey a wealth of information between individual spiders. Males and females perform elaborate signaling with their motions and positioning to coordinate mating. Rivals also signal their aggressive motivations with characteristic patterns of leg raises and waves. Spiders have an innate biological “language” of movements that helps their societies function!
| Spider Behavior | Message Conveyed |
|---|---|
| Leg tapping | Courtship and desire to mate |
| Zig-zag motions | Flirting and invitation to mate |
| Short waves of front legs | Territorial threats |
| Raised front legs | Aggression and intent to attack |
| Crouched posture | Defensive and willingness to fight |
| Curled up legs | Submission and surrender |
So while spiders don’t truly “wave” at each other, their species have evolved a rich lexicon of leg and body motions that serve as signals to other spiders. These displays are vital to communication between spiders in courtship, territoriality, and aggression.
Famous cases of spiders appearing to wave at humans
While most spider waving is misinterpreted human behavior, some viral videos and stories of seemingly “waving spiders” have captured public fascination:
Peacock spider waves
Male peacock spiders are tiny jumping spiders with colorful abdominal flaps they display to females. In courtship, they extend a leg and rhythmically raise and lower it like waving. Viral macro videos of this behavior enthralled millions with the “cute” spider’s seeming greeting. But it’s just their instinctual mating dance.
Newton the waving spider
A house spider in England was recorded on video appearing to wave back when a boy greeted it. Dubbed Newton the Waving Spider, the story went viral as a fun case of interspecies communication. But arachnologists chimed in that it was likely just coincidental motions, not true waving.
Petra the waving tarantula
In 2016, a family posted a video of their pet Chilean rose tarantula Petra. Petra repeatedly raised her front leg when the family waved and said hello. Many found this behavior astonishing for a spider. But others argued it was likely just payment conditioning, not comprehension of waving.
These and other incidents capture public imagination about the possibility of spiders intentionally waving at humans. And while that can’t be ruled out entirely, most spider experts remain convinced it’s instinctual behaviors misconstrued as waving. Nevertheless, these stories continue to compel our sense of wonder about the possibility of connections across the spider-human divide!
Conclusion
When a spider lifts its leg and waves it at you, it’s easy to imagine it signaling a friendly hello. But to scientists, the spider is likely not purposefully waving but rather exhibiting innate behaviors: sensing its environment, displaying aggression, or preparing to attack. While captivating anecdotes exist of spiders seemingly waving back at humans, these remain isolated incidents. Overall, spider waves aimed at humans are misinterpreted motions due to the spider’s limited vision, intelligence, and sociality rather than efforts at cross-species communication. Their waves are not for us, but for each other. With better understanding of spider biology and ethology, we can appreciate spiders for the complex creatures they are without projecting our own motives onto them. The next time a spider waves your way, enjoy a moment of whimsy pondering if it just might understand you! But also respect the spider’s reasons for motion as it acts and reacts using its own “language” tuned over 400 million years of evolution.