Spiders are super diverse creatures, in ways you can't possibly even predict. Last week this was demonstrated with a couple of species, both of which barely millimetres in size, yet one can create 25 metre wide webs in a single morning, and the other can jump 50 times its own distance, problem solve and hunt other spiders thrice its own size.

But these are things you typically expect from spiders; webs and hunting other spiders. These are typical characteristics of 'em, like the females eating the males or being as big as a dinner plate

But spiders can pull weirder things out of the hat than that, two of which I present to you today:

Fish eating spiders

Most of us have heard of the Bird-eating spider, or 'Goliath Birdeater', but for one, they don't rarely eat birds (though they certainly can, it's mostly opportunistic), but they're also not even the only spider that has been observed devouring birds. Others include the Golden Orb Weaver (which I had the pleasure of meeting in 'nam) and the Brazilian salmon birdeater.

Speaking of salmon, it's less known that there are spiders the subsist on fish! In fact, it's not even rare. Fish-eating spiders have been found on every continent that spiders can be found. As in, every continent except Antarctica.

One study in 2014 has reviewed eighty types of spider from a variety of families that prey on fish in lakes, ponds, swamps, streams, rivers and so forth.

And these aren't lazy spiders that sit around in some water-web waiting for its prey to stumble into its death trap. These are fast hunters, able to literally catch free-swimming fish from below, like this six-spotted fishing spider:

Diving spiders

As you can see, this spider uses surface tension to keep it afloat above the water, using its tiny, sensitive feet hair to detect movement. But some can actually dive beneath, *for up to an hour*, by way of collecting oxygen from bubbles between the hairs surrounding its 'book lungs', a kind of gill-lung hybrid.

And they don't come up with pathetic little baby fish either. Some species, like the , catch prey up to 3 times its own size.

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Dolomedes facetus, Australia (obviously)

Diving Bell Spider

But purely because they can, some take it even further. The diving bell spider lives its entire life underwater. It still needs to breath air, however, so evolution came up with the idea of creating a bell-shaped web that can capture an air bubble it depends on to breath, occasionally coming up to the surface once a day to collect some replenishing oxygen.

It does this by swimming up, sticking its arse out of the water and letting air get caught between its hairs, before dragging it below to its little web net.

In this niche environment, the diving bell spider can enjoy plenty of tiny shrimp, fish and other meals among the vegetation.

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So these spiders have given up terrestrial meat, I get that, but what if, like me, the spiders hate the taste and smell of seafood? Well, enter Bagheera.

Bagheera kiplingi

It seems kind of pointless being a spider if you're not going to be a vegetarian like the B.Kiplingi, I mean, catching blood-circulating creatures is what webs are for, right?

It turns out that webs are actually used for a huge range of things, from the aforementioned underwater airdomes, to stabilizing safety cables when leaping from tree to tree and more.

The Bagheera kiplingi, therefore, doesn't technically break any spider laws, but it is the only vegetarian spider yet discovered.

Bagheera is another wonderful species of jumping spider. But rather than strategically work out the most efficient killing strategies, this spider basically scavanges acacia leaves from ants who live symbiotically with the acacia shrubs; the ants protect the shrub, the shrub provides a home.

Bagheera has to live pretty carefully, avoiding ant guards at all times, and so it tends to hang out on the end of old, unguarded leaves, and if caught the spider simply absails down with its web. See? It has a use after all.

The spider is so successful at this that its diet is almost exclusively leafy, with up to 90% of its diet on this single acacia bush. The rest of its diet may come from nectar or even ant larvae.

If it does have to go for the larvae, Bagheera can even mimic spider movements in an effort to get them off its back.

So there you have it; spiders aren't always evolved to basically sit in the corner of your bedroom ceiling, watching your every move, waiting for the best time to crawl into your nose. Sometimes they just want to chill at the riverside eating veggies and fish.

Image sources

Golden Orb Weaver
Dolomedes facetus
Diving Bell spider
Bagheera kiplingi

Previously:

Convergence
Stupid Design
Weird Evolution
The Axolotl
Mutual Symbiosis
Parasitic Symbiosis Part 1
Parasitic Symbiosis Part 2
Weird Sex Part 1
Weird Sex Part 2
Humanity in Nature
Amazing Ants Part 1
Amazing Ants Part 2
Spiders Part 1

Vegetarian and pescetarian Spiders. Yep.

Fish eating spiders

Diving spiders

Diving Bell Spider

Bagheera kiplingi