Scientists are trying to solve the mystery of these big crabs’ colorful differences. Photo Credit: John Tann
Coconut crabs (Birgus latro) are gigantic land-dwelling crabs found on islands throughout the Indo-Pacific. They can live for decades, and can grow to be more than 3 feet wide (legs outstretched) and weigh in at more than 6 pounds. So that name isn’t because they’re the size of a coconut—it’s because they can actually tear open coconuts to eat their tender meat.
“If a coconut falls out of a tree, they’ll clamp onto it on the top and then drag it back to their husking ground,” explained Victoria Morgan, a PhD Candidate in the Department of Evolution and Ecology at University of California, Davis. You can always tell where a crab hides out by the piles of coconut husks lying around.
And it just so happens that out these massive, tree-climbing crabs come in multiple colors. They start out white as juveniles, when they act like other hermit crabs and don a protective shell. Then, as they mature and grow, they turn either red or blue. Really, really red, and really, really blue. “It’s weird that the colors are so distinctive,” Morgan explained. Stark color differences within a species, or color polymorphisms as scientists call them, are found in other crab species, but they’re generally in young animals. Continue reading “Red, White and Blue Crabs: These Tree-Climbing, Bird-Killing Crabs Come in Multiple Colors and No One Knows Why”
The dreaded tiger shark (Galeocerdo cuvier) is among a tiny minority of fish species (<1%!) whose distributions span oceans, according to a new paper. Range map from FishBase, picture of shark by Albert Kok.
Fifty-five years ago, Jack Briggs determined there were 107 fish species with a trait most fish cannot boast: a global distribution. These circumtropical species can be found in all tropical oceans, having found their way around the land masses which split the seas (at least often enough to persist as a single species). Now, in a publication for the journal Fish and Fisheries, Briggs has teamed up with Michelle Gaither, a postdoctoral research associate at Durham University, UK, and colleagues from the University of Hawaii and the California Academy of Sciences to update the half-century-old list. Of the over 20,000 marine fish species, a mere 284 span the seas to maintain a global distribution.
The team was able to re-evaluate Briggs’ original list thanks to breakthroughs in DNA sequencing that have occurred over the past 50 years. By looking at genetic sequences rather than just morphological differences, scientists are able to not only separate similar looking species, they are able to determine whether a single species is split into distinct populations or whether individuals are able to travel vast distances to keep disparate areas connected. Thanks to genetic data, nineteen of the original 107 have since been shown to be complexes of multiple species or not to make it around the globe, while 196 new species have joined the 1% club. Continue reading “What It Takes To Rule The (Marine) World”
Invasive species extraordinaire and one helluva toxic toad. Photo by Chris Ison
At the time, it seemed like the logical thing to do. Australian farmers were desperate. It was the 1930s, and beetles were tearing through their crops, especially sugar cane. Word spread of a toad that loved to gorge itself on the problem pests, which had been successfully brought to Hawaii to manage beetles in sugarcane fields. The Australians could have turned to pesticides, sure, but pesticides are expensive and often harmful to people and the environment. And if the toad could be introduced once, why not again? Why shouldn’t they fix their bug problem once and for all with a harmless little amphibian? So in 1935, two suitcases of cane toads (Rhinella marina; formerly Bufo marinus) arrived in Australia.
A new fossil, named Tetrapodophis amplectus, claims to be a four-legged, burrowing snake. (A) Counterpart, showing skull and skeleton impression. (B) Main slab, showing skeleton and skull impression. Figure 1 from Martill et al. 2015
Snakes, with their sleek, slithering shape, are unmistakable amongst the reptiles. Yet for decades, scientists have been debating just how these limbless lizard relatives ended up with their distinctive, elongated body.
On one side are scientists who argue that the serpentine shape was an aquatic adaptation. Many snake traits, including an elongated body and reduced limbs, are also features of swimming animals (think whales and dolphins, for example, which have lost their hind limbs). Early evidence also suggested that snakes were closely related to mosasaurs, the terrifying and extinct group of lizards that were woven into pop culture the moment one was fed a great white shark in Jurassic World. Non-theatrically, these marine reptiles ruled the seas during the Cretaceous, and possessed many snake-y features, including a jaw which stretches for large prey. The discovery of extinct marine snakes with hindlimbs, including Pachyrhachis, Haasiophis, and Eupodophis, seemed further proof of a marine origin.
But later analyses have suggested that Pachyrhachis and others are secondarily marine, the offshoots of a more derived snake group, and the connection between snakes and mosasaurs has come under suspicion. The prevailing hypothesis is now that snakes evolved on land — or, even more specifically, in it. A burrowing or ‘fossorial’ lifestyle could also produce long, skinny bodies and reduced limbs. More recent finds like Najash, Dinilysia, and Coniophis, which date back further than Pachyrhachis, all lived on land. But the evidence for a largely underground existence isn’t conclusive, either, and some hold to the idea that snakes were born in the sea.
The debate has continued so long because there is a dearth of snake fossils to rely upon. Snake bodies are by and large small and fragile, with thin bones that do not lend easily to fossilization. So scientists have had little material to work with when trying to determine changes over time.
A new fossil hopes to end the debate once and for all. A paper published this week in Science describes what appears to be a four-legged burrowing snake from Brazil. “Here it is, an animal that is almost a snake” says David Martill, a paleobiologist from the University of Portsmouth, “and it doesn’t show any adaptations to being in an aquatic environment.” But is it really that cut-and-dry? While the latest fossil find is making a splash in the news, it’s one of four noteworthy papers this year examining snake evolution, and placing the new study in context helps explain what makes the fossil so exciting, if controversial. Continue reading “Four-Legged Snake Shakes Up Squamate Family Tree – Or Does It?”
The tiny opening to Devil’s Hole, Nevada, where the most endangered pupfish in the world is found. Photo by Stan Shebs via Wikipedia.
The salt-encrusted earth of Death Valley is, quite literally, the hottest place on Earth. It is desolate terrain where even the most rugged life is constantly struggling to survive. Staring out across the dusty landscape, it’s hard to imagine that the entire area sits atop a vast aquifer, with millions of gallons of fresh water hiding below the arid surface. It’s even harder to believe this land was once a lush basin, where spring-fed pools and streams supported an abundance of life. Now, what remains from this fertile time can only be glimpsed where the ground has been torn open by earthquakes—deep, jagged fissures like Devil’s Hole.
The smooth, near-vertical walls of Devil’s Hole are hardly welcoming. Yet year after year, scientists climb the dangerous descent. Their goal? To count the few remaining fish that live on a small shallow shelf in these dark, warm, oxygen-depleted waters. These fish—the Devil’s Hole pupfish—are considered to be some of the most endangered fish in the world. They’re completely cut off from all other pupfish species, having lived in Devil’s Hole for countless generations, unable to reach their nearest cousins. In the spring of 2013, there were only 35 pupfish found during the September count. Only 35 members of this entire species left on Earth. Continue reading “The Unexceptional Devil’s Hole Pupfish”
Prialt, a revolutionary painkiller 1,000 times as strong as opiates without the addictive side effects.
Aggrastat. Byetta. Captopril. Integrilin. Prialt. What do these drugs have in common? Not what they’re used for, certainly. From angina to diabetes, they treat different diseases or conditions, and all have very different markets. They’re sold by different companies and were discovered in different laboratories around the world. But all have one simple thing in common: they come from animal venoms.
“All men by nature desire to know. An indication of this is the delight we take in our senses; for even apart from their usefulness they are loved for themselves; and above all others the sense of sight” – Aristotle
I see you! A sea star’s compound eye (red spot). Image credit Dan-Eric Nilsson, Lund University
Human beings are very visual animals. We rely on our sight more than any of our other senses to interpret the world around us, which is why over the centuries many have argued (and many still do) that sight is our most important sense. But, of course, we aren’t the only species that can see. Arthropods are particularly known for their acute vision, as are squid, octopus and other cephalopods. Yet although we’ve known about sea star eye spots for hundreds of years, no one knew whether they, too, are able to see images. That is, no one knew until Drs. Anders Garm and Dan-Eric Nilsson decided to investigate.
You would always be smiling, too, if you were high as a kite. Photo by Flickr user jeffk42
The BBC will be airing a cool new underwater documentary on Thursday called Dolphins: Spy in the Pod, where carefully disguised cameras were used to film the daily lives of everyone’s favorite marine mammals. But the most interesting detail seems to have been leaked on Sunday: during the documentary, some of the dolphins reportedly used a pufferfish to get stoned.
“Even the brightest humans have succumbed to the lure of drugs and, it seems, dolphins are no different,” said The Sunday Times. The article goes on to describe how the team got footage of dolphins gently harassing a pufferfish, which led to the dolphins entering “a trance-like state after apparently getting “high” on the toxin.”
“After chewing the puffer and gently passing it round, they began acting most peculiarly, hanging around with their noses at the surface as if fascinated by their own reflection,” said Rob Pilley, zoologist and one of the producers of the documentary. “This was a case of young dolphins purposefully experimenting with something we know to be intoxicating.” And so it would seem that we can add drug use to the long list of dolphin bad behaviors, (a list which includes bullying, rape and murder, for the record; illicit drug use seems a minor offense in comparison).
Introduced bee on a native ʻōhiʻa flower. Photo by Flickr user Zesuri
As most of my friends on the mainland don longer sleeves and more layers, it’s hard not to be a little smug about living in paradise. While, in their neighborhoods, leaves are falling off of trees and icy winds threaten to bring snow, I can throw on a T-shirt and shorts, grab a picnic basket, and hike to a scenic overlook for lunch. But Hawaii’s ever-sunny weather comes with one side-effect that can be deadly serious: year-round, Hawaii has bees.
Here Be Dragons: first written on the Hunt-Lenox Globe c. 1510 as the latin phrase HC SVNT DRACONES.
To a mediaeval mapmaker, the world was a vast and scary place. Explorers that braved the seemingly endless oceans in search of new worlds often didn’t return, and those that did carried with them nightmarish tales of monsters and serpents. It was the mapmaker’s task to warn future travelers of the dangers that awaited them in far-off lands. Based on their drawings, I cannot even begin to imagine the beasts that haunted these cartographer’s dreams. Their creative expressions of fear were eventually distilled into a single, ominous phrase: here be dragons.
Lands that still deserve this cartographer’s omen, however, can be counted on one hand. They are the Indonesian islands of Rinca, Gili Motang, Flores, and Komodo — the only places in the world where dragons still roam. Continue reading “Here Be Dragons: The Mythic Bite of the Komodo”
