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Cotton spinner sea cucumber

Cotton spinner © Paul Naylor/marinephoto.co.uk

Bizarre Bums

In the animal kingdom, bums can do so much more than just poo!

A group of froghopper nymphs on a plant stem. The nymps are covered in a layer of bubbly foam known as cuckoo-spit

Young froghoppers in 'cuckoo-spit' © Brian Eversham

Froghopper

Have you ever spotted frothy white bubbles all over a plant stem? We call this foam 'cuckoo-spit', but it doesn't come from a cuckoo! It's created by young froghoppers, a type of bug. They hide inside it to avoid predators. They make the foam by blowing bubbles from their bum!

Cotton spinner sea cucumber

Cotton spinner © Paul Naylor/marinephoto.co.uk

Sea cucumber

These sausage-shaped sea creatures are related to starfishes. They breathe through their bum, but also have a secret weapon back there. If they're in danger, they can fire out some of their organs! The sticky mess distracts predators whilst the sea cucumber escapes.

Dragonfly nymph

Dragonfly nymph © Niall Benvie/2020VISION

Dragonfly nymph

Young dragonflies suck in water through their butt and hold it inside them. This helps increase the pressure inside their body, which lets them fire out their mouthparts incredibly quickly to grab their prey. They also shoot the water out like a jet pack, and breathe through their bum!

A bombardier beetle standing on a rock. It's a red beetle with black wing cases and fairly long antennae.

Bombardier beetle © Brian Eversham

Bombardier beetle

These brilliant beetles take bum-based defence to the next level! When they're threatened, they fire bursts of burning hot liquid out of their bum to hurt their attacker. This spray is around 100 degrees Celsius and can quickly kill other insects!

A gem anemone on the sea floor. It has a green mouth surrounded by dozens of bluish tentacles with white oval spots

Gem anemone © Justin Hart, Alderney Wildlife Trust

Sea anemone

Some creatures, like sea anemones, don't have a mouth and a butt - they use the same opening for both. That's right, they eat with their bum! Or poo from their mouth, depending on how you want to look at it. Either way, it's pretty gross!

A female glow-worm clinging to a grass seed head. Her bum is glowing a bright greenish-yellow to attract males.

Glow-worm © @tomellisphotography

Glow-worm

These bizarre beetles might not spray deadly chemicals out of their bum, but their backsides are still pretty impressive. Female glow-worms glow in the dark! Their rear ends light up a yellowish-green colour, to attract any males that are flying by. When animals create light like this, it's called bioluminescence.

A bordered orbweaver sitting on its web, with dew drops clinging to the threads. It's a pale brown spider with a pattern of lighter crescents on its back

Bordered orbweaver © Jon Hawkins - Surrey Hills Photography

Spider

Spiders have some pretty useful tools stuck to their bums: a set of little nozzles called spinnerets. These produce the webbing that spiders use to catch prey, protect their eggs, and even ride the wind! Spinnerets are not part of the butt, so although it might look like it, spiders don't actually poop their webs.