How come you never see a tarantula stuck in the bath?

Well, it’s probably because you don’t live in the jungle but even if you did, you’re still extremely unlikely to see a Costa Rican zebra tarantula in your bath.

For most of us, it’s an all too common experience to stumble bleary eyed into the bathroom only to be shocked into full consciousness by the beady eyes of a huge common house spider sitting in the bath. The kinder souls among us lay out a spider ladder (a piece of toilet roll draped over the side of the bath) so that the spider can crawl out at its leisure. As whilst spiders have hairy feet, they’re not hairy enough for them to be able to stick to the smooth side of a bath like a gecko could.

Raiders of the Lost Ark

Spiders have exoskeletons and the bigger they are, the more likely they are to damage them. So, a common house spider could make many attempts to climb the side of a bath and fall back each time without hurting itself, but because of its size, a tarantula has to be much more careful. A fall from even a few centimetres can shatter its exoskeleton – a tarantula met its end this way when dropped during the filming of Raiders of the Lost Ark.

Silky spider feet

Since tarantulas have so much to fear from a fall, they make sure that they’re not likely to come a cropper. Researchers from the University of California analysed a tarantula’s footprints as it walked up a glass wall and found that it left behind little sticky patches of silk. When they looked closer they found that they had tiny silk producing spingots on their feet giving them an extra sticky hold.

So, the reason why you won’t find a Costa Rican zebra tarantula in your bath in the morning is that it’s already escaped…

Find related websites about spider silk with physics.org

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