Watchly Safety Review

How Do Spider Legs Actually Work?

Mark Rober

1:25 · 69.5M views · September 27, 2025

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Minor FlagsReviewed June 2026

2Minor Flags

1No Issues

This short science video is safe and genuinely educational for most kids, explaining how spider legs work through hydraulics with a fun live demonstration. The only minor concern is a subscribe prompt mid-video, but it's brief and doesn't overshadow the strong STEM content.

Content Breakdown · 3 Categories

Strong & Crude LanguageNot present

The video contains no profanity or crude language; the only mild exclamation is 'Oh, crud,' which is a very mild, child-friendly substitute for stronger language.

See evidence (1)

“'Oh, crud. Where'd it go?'”

Parasocial & Emotional ManipulationA little

There is mild audience-engagement language ('Stay with me,' 'I swear you're going to love this,' 'You got this') and a subscribe prompt tied to a payoff moment, but these are low-intensity and typical of educational short-form content rather than manipulative dependency-building.

See evidence (2)

“'Stay with me for a second, even if you hate spiders, cuz this is incredible.'”

“'And if this works, you have to subscribe to see more cool stuff like this.'”

Engagement Baiting & Manipulative CTAsA little

The video includes a subscribe prompt tied to a dramatic reveal moment ('if this works, you have to subscribe'), which is mildly coercive in framing but does not rise to guilt-tripping, superstition-based CTAs, or fake giveaways.

See evidence (1)

“'And if this works, you have to subscribe to see more cool stuff like this.'”

What Parents Need to Know

This video does an excellent job of teaching kids about hydraulics — a real engineering and biology concept — by connecting it to spiders and a giant excavator. The presenter uses a dead spider to demonstrate how fluid pressure controls leg movement, which some younger or more sensitive children might find unsettling, though it's handled matter-of-factly and not in a gross-out way. There is one subscribe call-to-action woven into the demonstration, but it's low-pressure and doesn't dominate the video. Overall, this is a high-quality, curiosity-driven science video that encourages kids to think about biology and engineering in an accessible, engaging way.

Talk to Your Kids About

1Can you explain what hydraulics means and where else we might see it used besides spider legs?
2Why do you think spider legs curl up when a spider dies? What does that tell us about how their bodies work?
3The video used a dead spider for the experiment — how did that make you feel, and do you think it was a good way to learn?
4If you could use hydraulics to build something, what would you make and why?

Protected Viewing

Frequently Asked Questions

What age is this video appropriate for?

We recommend this video for children aged 7 and up. The content is educational and not graphic, but the use of a dead spider in a hands-on experiment may be mildly unsettling for very young or sensitive children.

Is the spider content scary or disturbing for kids?

The video does feature a dead spider being manipulated with a small pump, shown up close. It's presented in a calm, scientific way with no gore, but parents of spider-phobic or very young children may want to preview it first.

Does this video contain any advertising or sponsored content?

No sponsored content or paid promotions were detected in this video. There is a brief subscribe call-to-action mid-video, but it's not aggressive or manipulative.

Is the science in this video accurate?

Yes, the explanation of hydraulics and how spider legs use hemolymph (blood) pressure to extend is scientifically accurate. It's a well-established biological fact presented in a simplified but correct way.

What will my child learn from watching this video?

Kids will learn about hydraulics — how fluid pressure can create movement — and how spiders apply this principle biologically to move their legs. It's a great entry point for discussions about engineering, biology, and how living systems work.

Is there any inappropriate language in this video?

The only mild language is the presenter saying 'oh, crud,' which is a very minor, non-offensive expression. There is no strong or inappropriate language throughout the video.