The Anatomy Of Tarantula Paws

tarantula paws
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Even the biggest arachnophobes have a really hard time denying that tarantula paws are extremely adorable and precious. In 2017, this became a well known fact when a few posts about tarantula paws went viral on social media, prompting even those who were scared of spiders to say a big collective “awwww” when looking at these little fluffy feet! I mean check it…the internet pretty much flipped out!

Let’s just say the internet was SHOOK! But there’s much more to tarantula paws than just their cuteness – the anatomy of a tarantula paw and its purposes is actually pretty fascinating!

Tarantula paws are technically spider claw tufts, or dense pads of hair and they are used by the spider for many different things. As far as their appearance, Arachnologist Norman Platnick from the American Museum of Natural History noted “the similarity to dogs or cats is only in the mind of the beholder.”

“Claw tufts occur in a number of spider families that can run up vertical surfaces like walls and glass,” added Robert Raven, head arachnologist at the Queensland Museum.

While all spiders have those hair-like structures called setae on their legs, not all have the claw tufts, which is the hairy pad around their clothes. Platnick said:

“About half of the spider families have claw tufts. These animals usually have only two claws at the tips of their legs, and are usually hunting spiders, who pursue their prey. Web-building spiders typically have three claws; the two paired claws, like those found in hunting spiders, plus a third, smaller, unpaired claw that helps them maneuver on their silk threads.”

tarantula paw
Photo credit: Wikimedia Commons

Another cool fact is that tarantulas use their feet and claws for many more things than cats and dogs – such as sticking on things (like the glass of their enclosures), and climbing any surface imaginable. Platnick said:

“The claw tufts of these spiders provide additional adhesive properties, making it easier for the animals to climb,” Platnick says. “For example, many tarantulas can even climb up glass, despite their relatively heavy weight.”

The tiny feet on tarantula paws are small and flexible, so they can make contact with many parts of a surface, which enables the tarantula to use them even upside down. The tarantula paws can temporarily attach their paws to a surface with this ability, as Jonas Wolff, a biologist at the University of Kiel in Germany, pointed out:

“Permanent attachment systems, like glue, are often much stronger and not reusable, whereas temporary attachment systems, like hairy adhesive pads, can be used multiple times [and] adhere strongly enough to hold the animal, but the contact can be loosened very quickly and effortlessly.”

Raven actually explains that this adhesion mechanism that tarantulas and other spiders use to climb surfaces is due to the van der Waals force, the electrical attraction between molecules that are very close to each other. You can’t see this with the naked eye, but each individual hair in the tuft is covered by hundreds of thousands of smaller hairs, called setules, that are only visible with an electron microscope. In studies, it was estimated that a jumping spider had about 600,000 setules on their 8 feet, and when adhered to a surface it allowed the spider to carry 173 times its body weight! Larger spiders like tarantulas may have even more setules to support their weight. Raven explained:

“Yes, van der Waals forces are most of the explanation” for why spiders have ‘furry paws’. However, there are two ways to go with this: if you are big you can get those beautiful big, dense iridescent pads as with the Idiommata; or you can get lighter, thus needing less, as in the case of huntsman spiders, which are among the few spider groups – along with jumping spiders – that can run upside down on ceilings and dangle off them with a toad in their fangs.”

tarantula paw
Photo credit: Wikimedia Commons

Another interesting ability of tarantula paws is that spiders can actually use them to “hear” and “smell.” I did a whole video about whether or not tarantulas can hear, but the smelling thing is new to me! Apparently, the modified setae on the last segment of their legs is what tarantulas use to sense. Platnick explained:

“For example, many spiders have trichobothria [vertical hairs] that are extremely sensitive to both airborne and substrate vibrations (i.e., they ‘hear’ with their feet). Many spiders also have modified setae that are chemosensory (i.e., they also ‘smell’ with their feet).”

The Australian Museum believes these hairs are so sensitive to vibrations in the air that spiders can actually sense the wings of an approaching insect!

Another interesting fact is that researchers believe that tarantulas use the smell sensors in their feet to find their way home – although, they are not really sure what scent they are following. Perhaps each tarantula has a certain scent they leave behind that they can trace?

Needless to say, we still have a lot to learn! You can see even more tarantula paws here!

By the way, check out my new tarantula magazine for more cool spider stuff:

I’m putting out issues every 2 months! If you’d like to be a part of that, you can visit the magazine’s Patreon page to subscribe or make a submission! You can also contact me at theavenmag@gmail.com for more info!

If you want to learn more about tarantulas, feel free to check out my big tarantula guide (I talk about lots of tarantula facts and enclosure/care tips). You can also get free tarantula tips by signing up for my newsletter or subscribing to my YouTube channel! I release new tips every Tuesday for Tarantula Tuesday! And I also sell some pretty cool tarantula t-shirts, if I do say so myself 😉