Yellow-bellied three-toed skink



This Australian reptile has been caught in the act – of evolving. One population gives birth to live young while another lays eggs. Yet they can interbreed and are clearly the same species.



By observing the skinks, we can see the evolution of live birth as it happens, and work out why some animals gave up the habit of laying eggs.



Read more: "Live birth, evolving before our eyes"



(Image: Chris Rehberg / Where Light Meets Dark)

Long-eared desert bat



Deadly scorpions? Dinner, thinks the desert long-eared bat. From a few metres above ground it drops onto one and tries to bite into its head.



In retaliation, the scorpion stings the bat straight in the face.



The bat's response? Meh, whatever. Seemingly hardly noticing, it carries straight on, kills the scorpion and carries it home to eat at leisure – even if it gets stung by the fearsome Palestine yellow scorpion, which in rare cases can kill humans.



This animal has well and truly earned its title of the hardest bat in the world.



(Image: Charlotte Roemer/CC Share Alike 3.0)

Bone skipper



Back from the dead after being presumed extinct for 160 years, the bone skipper bounced back into the world this year after being rediscovered in Spain.



It was thought to be the first fly to be killed off by humans, but it turns out we didn't quite manage it.



It's a nocturnal animal that feeds on the rotten flesh of large mammals. Active only during the winter months, it reportedly emits a luminous glow from its large, orange head.



Read more: "Horror fly returns from the dead"



(Image: Daniel Martín-Vega) Advertisement

Syringammina fragilissima



In the late summer of 1882, a ship called the Triton cruised the chilly seas north of Scotland and dredged up the first specimen of a new group of organisms, the single-celled xenophyophores.



The species they found, Syringammina fragilissima, is exceptional. Most single-celled organisms are microscopic, but Syringammina regularly grows to a width of 10 centimetres, and sometimes twice that.



It surrounds itself with a crusty structure called a test, which is the largest object made by a single cell.



Read more: "Living beach ball is giant single cell"



(Image: Andy Gooday)

Great bustard



The great bustard is probably the heaviest living animal that can fly. The males normally weigh between 10 and 16 kilograms, but some can reach 21 kilograms.



By contrast the females normally weigh no more than 5 kilograms. This is the largest size disparity of any bird species, and it can mean only one thing: females prefer chunky males.



But the females aren't just picking the males for their weight. They have an eye for their necks and whiskers too.



Read more: "The heaviest animal in the air"



(Image: Alonso Carlos Sanchez/Getty)

Olm



A blind little amphibian with translucent skin – once thought to be an infant dragon – offers valuable clues in the quest for the elixir of life.



The olm is a small salamander that spends its whole life in cave water, and has no eyes or skin pigmentation.



They may be able to live for over 100 years, perhaps because of a hitherto unsuspected quirk of their metabolism.



Read more: "Secret to long life found… in a baby dragon"



(Image: Arne Hodalič)

Cacoxenus indagator



You're walled up in the dark and all your food has gone. You have to escape. But to get out you have to smash your way through a stone wall with your head – without even knowing if you're going in the right direction.



It might sound like a scene dropped from Saw XXIII, but this is how the fly Cacoxenus indagator begins its adult life.



In the same situation humans would struggle, but the fly knows exactly what to do.



Read more: "Houdini fly inflates head to break walls"



(Image: Erhard Strohm)

Spinoloricus x



It might not look like much, but this creature is one of the most remarkable ever discovered: the first complex animal known to survive and reproduce entirely without oxygen.



Plenty of single-celled organisms live quite happily without oxygen, but this beast is a complex animal with millions of cells.



It lives in sediments deep under the Mediterranean Sea that are thick with salt and hydrogen sulphide gas.



Read more: "The mud creature that lives without oxygen"



(Image: Roberto Danovaro, Antonio Dell'Anno et al)

Peppermint shrimp



This brightly coloured crustacean has a lifestyle that requires extreme pronunciation skills: it is a protandric simultaneous hermaphrodite.



That means it starts out as a male, but sometimes turns into a hermaphrodite with both male and female sexual organs if mating options seem thin on the ground.



Changing sex is costly, so they would rather not do it. As a result they all play an advanced form of "chicken" called the hermaphrodite's dilemma, in which everyone hopes someone else will change sex first.



Read more: "Shrimp plays chicken with its sex change"



(Image: Miguelverdu under a CC 3.0 share-alike licence)

Mummichog



There's an old joke that if the world was devastated by a nuclear war the only survivors would be cockroaches and Keith Richards, but the mummichog could give them both a run for their money.



This fish can cope with an enormously wide range of environmental conditions, unlike more stay-at-home species. It can also survive in levels of pollution that would kill almost anything else.



Not only that: it was also the first fish to be sent into space. Apparently it was fine with it.



Read more: "The toughest fish on Earth… and in space"



(Image: USGS/Nonindigenous Aquatic Species Database)

Oriental hornet



Humans are still struggling to master solar power, but one wasp is way ahead of us.



With a tiny solar cell built into its abdomen, the oriental hornet can generate a small electrical voltage in its cuticle.



Among several handy uses, it can use the extra jolt of energy from light to wake itself up – even if it's been anaesthetised.



Read more: "The solar-powered electric hornet"



(Image: Matti Paavola)