It’s been a good year for strange animals. Which is something you could probably say about every year ever because animals are strange. So here’s my Top Ten Strangest Animal Moments of 2013, ordered from most strange to slightly less strange. Most lists go the other way and end on a high note, but when you come out the other end of this one thinking, "That's slightly less strange than those other ones I just read about ten minutes ago," ... who cares, it’s Christmas!
1. The Skin-Feeding Caecilian
Following in the footsteps of the Surinam toad from French Guiana that implants its fertilised eggs into its skin, and the extinct Australian gastric brooding frog that would swallow its eggs so the tadpoles can develop in its stomach, some species of legless, wormlike amphibians called caecilians have developed a pretty unique technique for good quality parenting.
In April this year, Mark Wilkinson and Emma Sherratt from the London Natural History Museum described the first new caecilian species discovered in French Guiana in more than 150 years. The find gave them the opportunity to describe a rare and little-studied behaviour known as skin-feeding.
When caecilian babies hatch from their eggs, they’ll immediately start scraping off their mother's skin for food with their super-sharp baby teeth. Their mother doesn’t seem to mind. Once they’ve peeled her clean, the babies will fight over any leftover skin scraps, sometimes participating in a grotesque battle over the one piece. They’ll do this for about a month after hatching until they’re strong enough to go out on their own.
2. Sea Hares use Weaponised Goo
You just can’t beat that image.
Sea hares are a large genus of herbivorous mollusks that can weigh up to 2 kg. So-called because of the large sensory rhinophores that sit on their heads like bunny ears, sea hares expel gooey ink secretions, which can not only repel and distract their predators, but can also mask their senses of smell and taste.
Sea hares have two defensive glands in their mantle cavity. The ink gland sits on the roof of the cavity above the gill and produces a purple ink, and the opaline gland in the floor of the cavity under the gill produces a milky white, viscous secretion called opaline. If a sea hare is threatened or attacked, a siphon inside its mantle cavity will pump one or both of these secretions out into the surrounding water to act as a decoy or a repellent.
A new study published in March reported that the opaline secretion actively masked the chemosensory and motor neurons of the sea hares’ top predator - spiny lobsters. So much so, that in the experiments, the spiny lobsters didn’t even notice when food was offered to them right in front of their spiny lobster equivalent of a nose.
3. Sea Slug and Horrifying Head-Stabbing Sex
Last month Rolanda Lange from the University of Tuebingen in Germany reported a never-before-seen “head injecting behaviour” in a new species of unnamed sea slug - Siphopteron sp. 1. With double-barrelled penises that consist of a sperm-injecting penile bulb on one side and a syringe-like penile stylet on the other, hermaphroditic sea slugs in the genus Siphopteron are built to inject each other with different types of fluids while they mate.
While other species inject into the back or the foot, a pair of Siphopteron sp. 1 will dance around each other for a bit, maybe with some biting, before inserting their penile stylets deep into each other’s foreheads, right near the eyes, to transfer fluids that have been produced in the prostate gland. This has never been seen before in another animal species.
4. Super-Skinny Chameleon Battles
That video. That track with that video.
The biggest surprise to come out of this study, which was published earlier this month, is that when veiled chameleon males fight over territory or females, it doesn’t matter who’s the biggest or the strongest. A better indication of who’s going to win a chameleon battle is who can change colour the fastest and the brightest.
Also amazing is the almost literally mind-blowing ‘billboard’ effect these chameleons achieve as part of their territorial display. According to lead researcher Russell Ligon from Arizona State University, they can suck their bodies in to be about the width of your pinky, using muscles attached to highly specialised hinged ribs that slot into each other. They might also be able to somehow stack their elongated organs to make everything fit.
5. Antechinus has Sex until he Disintegrates
For the fifth strangest animal of 2013, I’ll let Ed Yong do the honours because I missed this one, which is shameful because it’s one of my countrymen:
It’s August in Australia, and a small, mouse-like creature called an antechinus is busy killing himself through sex. He was a virgin until now, but for two to three weeks, this little lothario goes at it non-stop. He mates with as many females as he can, in violent, frenetic encounters that can each last up to 14 hours. He does little else.
He exhausts himself so thoroughly that his body starts to fall apart. His blood courses with testosterone and stress hormones. His fur falls off. He bleeds internally. His immune system fails to fight off incoming infections, and he becomes riddled with gangrene.
Gross, antechinus, come on!
6. Thor's Hero Shrew: King of the Backbones
Thor’s hero shrew is number six on this list but is number one on the Backboniest List of All Time Until Someone Backbonier Comes Along. So that’s pretty good. And what better opportunity to celebrate this passage from Herbert Lang and Joel Asaph Allen’s 1917 paper again:
“Whenever [the Mangbetu] have a chance, they take great delight in showing to the easily fascinated crowd its extraordinary resistance to weight and pressure. After the usual hubbub of various invocations, a full-grown man weighing some 160 pounds (72 kg) steps barefooted upon the shrew. Steadily trying to balance himself upon one leg, he continues to vociferate several minutes. The poor creature seems certainly to be doomed. But as soon as his tormentor jumps off, the shrew, after a few shivering movements, tries to escape, none the worse for this mad experience and apparently in no need of the wild applause and exhortations from the throng.”
Thor's hero shrew don't need yo' applause!
A new species of Thor’s hero shrew was discovered in the Democratic Republic of the Congo in July this year. The team led by William Stanley from Chicago’s Field Museum of Natural History suggested that the hero shrews were using their long, fortified spines to leverage leaf bases away from tree trunks to gain access to a secret wealth of grubs and other insects.
7. Deep-Sea Squid's Not-So-Lame Tentacle
August brought us the first footage of the deep-sea squid species Grimalditeuthis bonplandi using a tentacle behaviour not seen in any other squid. Filmed by researchers at the Monterey Bay Aquarium Research Institute (MBARI) in California, the footage solves the mystery of how G. bonplandi survives with no suckers, hooks, adhesive pads or photophores on its tentacle clubs. In other words, none of the things that normal squids – ie all other known species of squid - use to catch prey.
Turns out G. bonplandi is using its lame tentacle kind of like a fishing lure. And the researchers suggest that it works in three ways. Firstly, by waving its tentacle clubs around, G. bonplandi could instigate a flash of bioluminescence by other organisms in the surrounding water to lure its prey into the area. Secondly, the club movements create low frequency vibrations that could attract certain prey animals such as crustaceans, fishes and cephalopods. And finally, the tentacle club movements create a wake, which could cause prey to move towards it, thinking it’s been produced by its own prey objects or a potential mate.
8. Tinkerbella, a New Species of Tiny Fairyfly
Discovered in Costa Rica in April, Tinkerbella nana is a new species of fairyfly that grows to no more than 250 micrometres. So a quarter of a millimetre. Named after a couple of Peter Pan characters, T. nana is completely invisible to the naked eye, and is closely related to the world’s smallest known winged insect - Kikiki huna, which has a body length of just 155 micrometres.
And even smaller than K. huna is the current smallest insect in the world – a male Dicopomorpha echmepterygis Mockford, found in 1997 and stretching a mere 139 μm long.
9. Hipster Toad has a Weaponised Moustache
And here I'll let Michael Marshall from New Scientist's Zoologger column announce our ninth Strangest Animal Moment of 2013:
For Emei moustache toads, a top-quality moustache is an essential, and violent, weapon ... During the breeding season, each male grows 10 to 16 spines. "They are as sharp as a pencil lead," says Cameron Hudson of the University of Guelph in Ontario, Canada, adding that the frogs "do try to stab you a bit when you pick them up".
The males fought underwater, head-butting each other in the belly to drive their spines into the other toad's flesh (see video). "I've never seen any of them kill each other," says Hudson. "But they get a lot of puncture wounds."
10. Australian Squid Eat Sperm for Better Bodies and Babies
In June, sperm consumption was reported for first time in female southern bottletail squids (Sepiadarium austrinum), a small species that lives in the shallow, coastal waters of southern Australia. And it looks like these females are using the nutrient-rich ejaculate to maintain steady egg production and strong, healthy bodies.
In a study led by Benjamin Wegener from Monash University in Melbourne, it was discovered that the small females consumed far more spermatophores than the larger females, presumably so they could produce higher numbers of healthier offspring than they could otherwise manage. The larger females, on the other hand, consumed less sperm, and were preferred by the males, probably because they pose less of a threat to their potential offspring.
So till next year, may your sex be head-stabby, your backbones be backbonier, and woe betide you if your colour-changing game isn't super-skinny.
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