biotaBOOM: October 2009

A fantasy nightmare come true

Hold onto your desk chairs, arachnophobes.

Never mind Shelob or Aragog - this is a real-life supermassive spider web in Lake Tawakoni National Park, in Texas.

While you hyperventilate into a paper bag, I'll explain this monstrosity further. The web was built by a colony of millions of spiders as a hippie-style communal home and trap for prey. Normally, spiders are solitary creatures, so the discovery of the enormous web (covering several hectares of the park) has stunned scientists.

According to this article, it "emits a fetid odour, perhaps from the dead insects entwined in the silk", and "whines with the sound of countless mosquitoes and flies trapped in its folds".

Scientists are still speculating about the actual spiders and the discovery of this rare behaviour. Meanwhile, the photograph is doing the rounds on the internet, and the Park staff are desperately trying to protect the "marvel".

Eeeeuegehghegheghghhhh.

"Miniature puffskeins!"

You might be forgiven for thinking there are some cotton plants sprouting up in the centre of this leaf. In fact, these tiny fluffballs are Honduran white bats (Ectophylla alba), native to parts of Central America.

HOW CUTE.

They reminded me at first of pygmy puffs from Harry Potter, except these are real. The bats grow to between a whopping 3.7cm - 4.7cm and are related to a species of bat known as the 'tent-making bat'. This is because they make tents. (The logic! It astounds!)

Honduran white bats live in small colonies on the underside of large leaves of the Heliconia plant. They make a protective 'tent' by using their teeth to cut along the midvein of a leaf, causing it to fall over slightly and form their shelter. This protects them from predators and the elements. And despite being white, the leaves provide them with excellent camouflage, because sunlight filters through the leaf and tints their fur green.

Mostly, however, they just hang around being really, really cute-looking.

Links:

Thanks to voguelady at Milk and Ink for bringing these to my attention.

An even better picture of the bats

Honduran white bats at Rainforest Alliance

What's in a name?

OK, multiple choice: which of the following are actual names of now-extinct species that once existed in Australia? (No Googling!)

a) Thingodonta, a particular order of marsupials

b) Fangaroo, an ancestor of the kangaroo which had fangs

c) The "Demon Duck of Doom", the nickname given to a fearsome-looking duck

d) None of the above - don't be stupid, this ain't science!

Is it a trap? Is the correct answer 'd'?

Nope. The answer is that a, b and c are all names of things that actually existed once upon a time. Their fossils were found in a now-famous deposit site called Riversleigh, in northern Queensland.

Riversleigh has yielded spectacularly-preserved fossils of creatures so bizarre that scientists have resorted to appropriately bizarre names for them. 'Thingodonta' is the colloquial name for an extinct order of marupials, one of which had teeth unlike that of any other animal. 'Fangaroo' was an ancient kangaroo with fangs. The 'Demon Duck of Doom' is the nickname given to Bullockornis, a massive (2.5m!) carnivorous flightless bird with a skull larger than that of a small horse!

There was also a gigantic platypus with teeth (Obdurodon dicksoni), a crocodile that climbed trees (Trilophosuchus), and a bird that was a cross between an emu and a cassowary, so they called it an 'emuary'. Genius.

There are so many incredible and bizarre creatures, I don't really have space to list them all here. However I've found some great links you can visit if you're interested, which are listed below. Plus, the Australian Museum in Sydney currently has an exhibition on about extinct animals from Australia's past, and there's a book that deals directly with the finds from the Riversleigh area.

Links:
Riversleigh fossils info - Australian Museum
ABC Science - Amazing Beasts
Amazing Australia: Riversleigh/Naracoorte fossil sites

What doesn't kill you, makes you stronger...

...and here is this popular saying, in animal form:

Seriously. Isn't that just incredible? Doing a Google image search on these is like confectionery for the eyes.

You may have heard of it before - this entry is about nudibranchs, more commonly referred to as 'sea slugs'. They're smallish marine creatures with striking colouring and a truly awesome defence mechanism.

Nudibranchs like to chow down on (amongst other things) sea anemones. This is significant because sea anemones have their tissues filled with little stinging buds called nematocysts, which are what anemones use to poison any prey that happens to get too close. And under normal circumstances, by all rights the nudibranch should be killed from eating anemones.

However, sea slugs have evolved the capacity to swallow these poisonous, stinging cells and remain completely unharmed by them. In a way, it's as though the nematocyst is a bomb, which the nudibranch manages to diffuse.

But better still, the nudibranch then absorbs these nematocysts into its own tissues - and then uses them to defend itself against predators. Sort of like taking a weapon from someone who was about to hurt you with it, saying "Thanks for that!", and then proceeding to use that weapon against someone else you didn't like.

Neat!

Links:

A ridiculous amount of information about nudibranchs

A National Geographic video clip about nudibranchs, featuring an incredibly annoying narrator

Three Bizarre Frog Facts: Part 3

Bizarre Frog Fact #3: This Frog Can Hold 50% Of Its Weight In Water.

The Water-Holding Frog, Cyclorana platycephala, is a weird Australian frog that lives in the desert and has a real thing for H2O. Whenever there's a severe water shortage (and hey, it's the desert...there's pretty much always a water shortage), it:

Stores ridiculous amounts of water (up to 50% of its weight!) in its bladder and pockets in its skin - this water is acquired when there's a sudden downpour of rain,
Uses its feet like shovels, and tunnels underground into the sand,
Secretes a layer of mucus out of its skin, and then hardens the outermost layer, forming a tough outer layer of dead skin - a bit like wrapping itself up in Glad-Wrap,
Stays there until there's enough rain to safely come out again. This can take years.

Nifty, eh?

More links about the frog:

Water Holding Frog: A Unique Creature

National Geographic video

Database Entry for Cyclorana platycephala

FrogWatch at the Western Australian Museum

Three Bizarre Frog Facts: Part 2

Bizarre Frog Fact #2: The Baby Frog Is Bigger Than The Adult Frog.

Picture this: you have a baby which is about five metres tall. As it 'grows' into an adult, it gradually shrinks to ordinary human size.

It all sounds very 'Honey, I Shrunk The [Whatever]!' in reverse. Or perhaps even a little bit Benjamin Button. But this is completely normal for the Paradoxical Frog, Pseudis paradoxa.

The frog's tadpoles grow to about 23cm long, and they gradually 'shrink' to become an adult frog of normal length, about a quarter of the length of the tadpole (up to 7.5cm long).

How odd.

Interestingly, scientists have also found that secretions from this frog could help treat people with Type 2 diabetes.

You can read more about the paradoxical frog in a book excerpt from the International Wildlife Encyclopedia (3rd ed.) on Google Books, if you're especially keen. Go on. You know you want to, really.

Three Bizarre Frog Facts: Part 1

Bizarre Frog Fact #1: Some Frogs Eat With Their Eyeballs.

OK, no, they don't actually consume food through their eyes. That would be a bit too bizarre. However, they do use their eyeballs to help push food down their throat.

A brief article about this crazy behaviour was published in Cosmos magazine recently, and it sums up the facts quite nicely:

"For the northern leopard frog (Rana pipiens), eyes are not only good to see prey with, they're good for swallowing it too. This contortionist of the animal world can retract its eyes into its head, and move them down towards its throat. The frog still uses its tongue to swallow, but the eyes offer a useful helping hand."

Don't try this at home, people. We are not frogs.

Quote source: Cosmos magazine, Issue 28 (Aug/Sept 2009), p.14

A fish with no table manners

Here is a picture of a fish, called a 'sling jaw wrasse':

And this is how it eats its dinner:

The jaw of this fish isn't firmly attached to its skill. Instead, the sling jaw wrasse can 'shoot out' its mouth in order to catch prey. These 'protrusible jaws' can extend to over half the total body length of the fish, and can reach into narrow crevices to grab more elusive food if it wants to. This incredible feeding mechanism is made possible by extra ligaments and rotational bone movements that other fish just don't have.

Weird...

Some more links for you:

The fastest jaw in the west (Pacific)!

Biodiversity of the Week: the sling-jaw wrasse