The animal kingdom has no shortage of weird and wonderful surprises, and this year biologists gave us some real treats to talk about at the dinner table. All walks of life, from microscopic bacteria to huge cetaceans have remarkable, varied adaptations, and the more we know about how animals interact with their environment, the better our chances will be of preventing extinction. And some adaptations also proved to be very amusing …
Octopus sleep like us, cuttlefish see with their skin
Researchers from the Okinawa Institute of Science and Technology (OIST) and the University of Washington examined the brain activity and patterning behavior of the Octopus laqueus and found that it experienced an active stage of sleep similar to rapid eye movement (REM) slumber. What's more, the animal's behavior during this time suggested that, like humans in REM sleep, an octopus might be dreaming, providing new insight into the animal's cognitive capabilities.
Meanwhile, in what was a big month for both the Japanese university and cephalopods, OIST and Max Planck Institute for Brain Research scientists unearthed fascinating new findings as to how the cuttlefish can precisely control and color-correct its camouflaging patterns, showing much greater brain function than previously thought.
Bats with huge heart-shaped penises work with what they've got
Researchers at the University of Lausanne, Switzerland, made some curious discoveries about a group of bats living in a church attic in the Netherlands. The bats had been captured on camera engaging in marathon sex sessions, which seemed a little odd. On closer inspection (all in the name of science, of course), they found that the male serotine bat (Eptesicus serotinus) was sporting a heart-shaped penis that, when erect, measured a fifth of the length of his 2.75-inch (7-cm) body and seven times longer than his partner’s vagina. Because of this, the scientists discovered, the bats were having non-penetrative sex, using their penis like an arm to push aside the female's tail to mate in a way similar to cloaca-contact sex in the bird world. It's the first-ever account of superficial-contact mating among mammals. (Click through to see photos of the bat's now world-famous features.)
This beetle, however, has a bottle-opener-shaped penis
Not to be outdone by bats, this European beetle was discovered to have a penis shaped uncannily like a bottle opener. The University of Copenhagen researchers that made this discovery on the newly found species of rove beetle then, fittingly, named it Loncovilius carlsbergi, paying tribute to Denmark's famous beer company Carlsberg. At the time of publication, the researchers were working on producing a bottle opener based on the beetle's penis, to raise awareness of insects – which are the most populous animal on the planet, yet also the most disregarded when it comes to conservation.
Female frog plays dead to avoid unappealing males
Adaptations for selective mating is common in female species, and scientists from the Konrad Lorenz Institute of Ethology, Vienna, discovered a particularly dramatic one this year. When bombarded with attention during 'explosive breeding' frenzies, the female European common frog (Ranat emporaria) will fake her own death to avoid mating with an undesirable male. Scientists believe the strategy evolved from tumbling in water, which can drown male and female frogs. So this act of playing dead is both a convincing and an energy-conserving one.
A group of ants were also found to be good actors (mostly)
In a first, scientists observed not one but a group of ants simultaneously faking their own death. While single ants playing dead have been recorded before, it's never been seen in a group of animals. The scene was discovered by accident, when University of South Australia researchers were investigating nesting boxes for native animals on Kangaroo Island. At first, the scientists thought the ants had died in the boxes, until one Polyrhachis femorata ant gave the grift away and was seen moving. They witnessed this curious behavior throughout the fieldwork, with some ants instantly triggered and others taking longer to get into character.
DNA distribution reveals sea stars to be all head, not arms
Upending what biologists know about sea stars, commonly known as starfish, researchers from Chan Zuckerberg Biohub San Francisco, working with labs at Stanford University and the University of California Berkeley, found that it has genetic markers for a head, yet none that code for a torso or tail. The genetic signatures for the head were localized in the middle of each of the animal's 'arms', leading scientists to believe the sea star is, in fact, more of "a head crawling along the seafloor."
Snake is seen reducing its own species biodiversity
While this kind of cannibalism is not entirely unusual in the world of snakes, recording it is. Nick Stock from Piccaninny Plains Wildlife Sanctuary in Australia (where else), photographed a large black-headed python enjoying a sizeable meal of another black-headed python. Despite the python's usual behaviors of constricting prey fatally before eating, this smaller snake was indeed consumed while it was still alive. The non-venomous, constricting python (Aspidites melanocephalus) is known to eat other reptiles and will opportunistically take a juvenile relative if it can.
Genetics reveal just how beetles drink with their butts
Scientists uncover the genetic mechanism that makes it easy for beetles to extract scarce water from their environment and absorb it through their rectum. The researchers from the University of Copenhagen, the University of Edinburgh and the University of Glasgow discovered that the red flour beetle (Tribolium castaneum) had one gene expressed 60 times more in the rectum than anywhere else in the animal’s body, and it was localized to a unique group of cells, key to this butt drinking. Because the beetle is genetically similar to other species such as the Colorado leaf beetle, scientists believe muting this genetic mechanism could make environments such as farmed grain crops uninhabitable for them.
Prolific pee-flicking bug uses physics to fling urine around
Scientists at Georgia Tech used high-speed video and microscopy to uncover how the glassy-winged sharpshooter (Homalodisca vitripennis), which urinates around 300 times its own bodyweight every day, manages to flick pee such great distances. And it's epic. The bug is adorned with an anal appendage dubbed a “butt flicker,” and this rear-end pinball paddles flicks drops of pee at 40 G’s, using physics never before seen in nature. The scientists believe that while it's fun to watch (check out the video in the link), this natural adaptation also has practical bio-inspired applications.
Meanwhile, this bug detaches its butt to send it off for mating
Because we couldn't get enough insect butt discoveries in 2023: University of Tokyo researchers unraveled the genetic mystery behind how the Japanese green syllid worm (Megasyllis nipponica) grows a ‘mini-me’ at its rear end, which it then deploys so it can swim off on its own in search of a similar autonomous tail of the opposite sex to spawn with. The worm, meanwhile, will then grow another, to deploy for mating once more.
Scientists find bug that can turn 'zombie mode' on and off in ants
In another first, University of Copenhagen scientists discovered how one cunning pathogenic flatworm can switch ‘zombie mode’ on and off, engaging in an intermittent hostile takeover when it best suits them. The parasitic lancet liver fluke (Dicrocoelium dendriticum), takes over the brains of European wood ants when the temperature is optimal, steering the ant up a blade of grass and waiting in the hope of feeding cows or sheep – the flatworm's final host – grazing past. If it fails and the temperature changes, the ant regains its faculties … until the next takeover, that is.
Parasite makes 'zombie shrimp' stand out from the crowd
Scientists at Brown University discovered how the parasite Levinseniella byrdi, which can only reproduce in the guts of certain marsh bird species, hacks the genome of its amphipod host to change its behavior and color in order to make it easy pickings for the host bird it needs. Using RNA sequencing, the scientists found that the parasitic worms activate genes that involve pigmentation, interfere with their ability to detect external stimuli, and suppress multiple genes involved in immune responses, which would otherwise fight off the parasite. Not so great for the formerly, elusive, camouflaged amphipod, but excellent for the parasite (and not too bad for the bird, either).
Researchers capture bird's insane 700-mile typhoon joyride
Thanks to GPS bio-loggers attached to 14 adult streaked shearwater (Calonectris leucomelas) seabirds, Tohoku University scientists found that one bold male threw caution to the wind, flying above Typhoon Faxai as the storm pummeled southeastern Japan. It was the start of an 11-hour, 1,146-km (712-mile) crazy journey that took the bird 4.5 km (15,000 ft) higher than normal, at three times its usual speed. The bird lived and the researchers gained incredible new insight into seabird migration patterns and how they may be adapting to more frequent extreme weather events.