by David Braun
Josep Quintana
paleontologist and study leader, on his initial thoughts upon discovering the N. rex fossil
Living Free and Easy
The newfound rabbit’s “roly-poly, tank-like” appearance and weird anatomy may have arisen because of its stress-free lifestyle, Kraatz added. That’s because the megarabbit had no predators on Minorca—a luxury that allowed the species to evolve to be bigger and more sedentary, he said. Modern rabbits are small, spry, and have sharp vision to escape predators. “He was probably on an evolutionary vacation,” said Kraatz, like an “islander beach bum.”
Yet, even though the giant rabbit “didn’t have too many cares or worries,” Kraatz said, “he got too comfortable, and eventually went extinct.”
CHAPTER 11
Under Water Weirdness
(Photo Credit 11.1)
Here there be weirdness! Early maps of the world often showed strange, terrifying monsters swimming in the seven seas, but krakens and sea serpents seem downright boring when compared to what scientists are finding today. One-eyed albino sharks, “walking” fish with hands, giant amoebas, and catfish the size of grizzly bears are living beneath the water’s surface, just waiting to surprise someone with their freakishness. So come on in. The water’s fine.
HERE’S LOOKING AT YOU, KID
Rare “Cyclops” Shark Found
It was a one-eyed, two-finned, swimming, albino people-eater that caught the world’s attention in 2011. How common are one-eyed sharks, and what could have caused this creature’s strange condition?
Talk about a one-of-a-kind discovery—an extremely rare cyclops shark has been confirmed in Mexico. The 22-inch-long (56-centimeter-long) fetus has a single, functioning eye at the front of its head—the hallmark of a congenital condition called cyclopia, which occurs in several animal species, including humans.
Endangered
Dusky sharks, which average about 10 feet (3 meters) long as adults, are among the slowest growing of the shark species and can live for up to 45 years. Often illegally harvested for its fins, the shark species is rated as “vulnerable” by the International Union for Conservation of Nature.
One-Eyed Monster
In 2011, fisherman Enrique Lucero León legally caught a pregnant dusky shark near Cerralvo Island in the Gulf of California. When León cut open his catch, he found the odd-looking male embryo along with its nine normal siblings. “He said, ‘That’s incredible—wow,’ ” said biologist Felipe Galván-Magaña, of the Interdisciplinary Center of Marine Sciences in La Paz, Mexico.
Once Galván-Magaña and colleague Marcela Bejarano-Álvarez heard about the discovery—which was put on Facebook—the team got León’s permission to borrow the shark for research. The scientists then x-rayed the fetus and reviewed previous research on cyclopia in other species to confirm that the find is indeed a cyclops shark.
Cyclops sharks have been documented by scientists a few times before, also as embryos, said Jim Gelsleichter, a shark biologist at the University of North Florida in Jacksonville. The fact that none have been caught outside the womb suggests cyclops sharks don’t survive long in the wild. Overall, finding such an unusual animal reinforces that scientists still have a lot to learn, Gelsleichter added.
“It’s a humbling experience to realize you ain’t seen it all yet.”
TRUTH:
ALBINISM IS A RARE CONDITION AMONG SHARKS, OCCURRING MORE OFTEN IN BONY FISHES.
The Eye Has It
The cyclops shark also has other deformities, including albinism, or a total lack of tissue pigments; no nostrils; a bump on its snout; and a spinal abnormality, according to Galván-Magaña. A mother’s poor diet—especially a lack of vitamin A—can cause cyclopia in mammals, including people, but it’s difficult to determine the cause of the condition in sharks, he said.
The cyclops baby’s eye, located in the middle of its snout, is about 1 inch (2.6 centimeters) wide. (Photo Credit 11.2)
Even so, Galván-Magaña suspects the defects in this case aren’t related to pollution. “The fishing area close to Baja California Sur is clear of pollution, is a pristine zone, and we cannot consider it as a cause for abnormalities in dusky sharks,” according to the study.
Aside from the handful of deformities, “the rest of the body was apparently normal,” with well-formed fins, according to the scientists’ study, which has been submitted for publication. Despite its lack of nostrils, the shark’s gill slits were normal and well formed, and its mouth contained small teeth, according to the study.
If it’d been born, the cyclops shark likely wouldn’t have lived very long, Galván-Magaña said. The baby’s stark white color would’ve made it more obvious to predators, and its malformed tail would’ve hindered swimming. There are no previous known cases of albino dusky sharks, “so this report is considered a first record of this malformation for this shark species in Mexico,” according to the study.
What’s in a Name?
Common English-language names for the dusky shark include bay shark, black whaler, bronze whaler, brown dusky shark, brown shark, common whaler, dusky ground shark, and shovelnose.
Fisherman’s Prize
After Galván-Magaña’s team completed their research, they returned the cyclops shark to León. He regards the cyclops shark as a prize, Galván-Magaña said, and has already preserved his oddity in alcohol. “Lots of people want to buy the shark, but the fisherman says no.”
KNUCKLE DRAGGERS
Fish With “Hands”
Found to Be New Species
Look Ma! They’ve got hands! Not much for swimming, the handfish family uses their fins to walk along the ocean floor. Here are some of our favorites.
All of the world’s 14 known species of handfish are found only in shallow, coastal waters off southeastern Australia. But about 50 million years ago, the animals likely inhabited regions around the world, as noted by Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) scientists. Fossils of the curious creatures have been discovered in the Mediterranean, for example.
Scientists have announced nine newly named species in a recent scientific review of the handfish family. The new-species determinations were made based on a number of factors, including number of vertebrae and fin rays, coloration, the presence of scales and spines, and proportional body measurements, according to review author Daniel Gledhill.
Even among the previously known species, the fish are poorly studied, the review authors add, and little is known about their biology or behavior. There’s much more to learn about these freaky fish.
Superfish!
Handfish aren’t the only fish with surprising skills. Check out these superfish:
1. Counting! Lab experiments have shown that the mosquitofish, a North and Central American freshwater fish, can count.
2. Walking! West African lungfish can both push off a solid surface and move along it using their pelvic fins.
3. Immortality? Swimming off the coast of Africa, the coelacanth can live up to 100 years and even longer.
FISH 1
New, Pink, and Rare
Using its fins to walk, rather than swim, along the ocean floor, the pink handfish is an elusive creature. Only four specimens of the 4-inch (10-centimeter) pink handfish have ever been found, and all of those were collected from areas around the city of Hobart on the Australian island of Tasmania. Though no one has spotted a living pink handfish since 1999, it’s taken until now for scientists to formally identify it as a unique species.
The elusive pink handfish is rarely seen in the wild. (Photo Credit 11.3)
FISH 2
See Spot Walk
The previously known spotted handfish is found on sandy sediments at the bottom of Tasmania’s Derwent Estuary and adjoining bays. The fish use their fins to walk along the seabed, where they eat small invertebrates such as worms and crustaceans. Perhaps the best studied species of the handfish family, the spotted handfish is listed as critically
endangered by the International Union for Conservation of Nature—meaning it’s “facing an extremely high risk of extinction in the wild in the immediate future.”
Handfish’s slow movements and tendencies to stay within tightly confined habitats would seem to make the fish easy targets for predators. But researchers think handfish have a secret weapon: a toxic skin that kills most attackers. Anecdotal stories suggest predators may die within an hour of eating a handfish, said CSIRO fish taxonomist Gledhill.
Scientists have studied the spotted handfish the most. (Photo Credit 11.4)
FISH 3
Seeing Red
The red handfish, a previously known species, is listed as vulnerable in Australia, where it’s found only around the southern island state of Tasmania. Not much is known about handfish, because their populations are low and they are not often seen in the wild. But researchers suggest handfish lay fewer eggs than most other fish species, which means their long-term survival is a concern. Handfish also tend to stay very close to home, so they don’t adapt well to new places, said fish taxonomist Gledhill.
The red handfish lives mostly off the coast of Tasmania. (Photo Credit 11.5)
FISH 4
Also Available in Purple
Newly described as its own species, the Ziebell’s handfish typically has yellow fins, but the species can also appear with a mottled purplish coloration. Ziebell’s handfish is found only in small, isolated populations off Tasmania and is listed as vulnerable in Australia.
Bright yellow fins typically adorn the Ziebell’s handfish. (Photo Credit 11.6)
FIRST PICTURES!
Wild Fish Uses Tool
Cockle Put to Clever Use
Once thought to be a distinctly human trait, tool use has now been observed in a wide variety of animals, including chimps, dolphins, crows, and octopuses. And now fish are getting in on the act, too.
A blackspot tuskfish off Australia used his noggin to get some dinner. A diver saw the fish take a cockle in its mouth and swim to a nearby rock. Then the fish smashed the cockle again and again against the rock until the shell cracked. Dinner is served, all thanks to clever tool use.
A blackspot tuskfish off Australia carries a cockle to a nearby rock. (Photo Credit 11.7)
Cockles, to Go
A recent study in the journal Coral Reefs says the pictures—snapped at a depth of nearly 60 feet (18 meters) in Australia’s Great Barrier Reef in 2006—are the first ever taken of a tool-using fish in the wild.
Professional diver Scott Gardner was just about out of air and swimming back to the surface when he heard an odd cracking sound nearby. Swimming over to investigate, he spotted the foot-long (30-centimeter-long) fish at work.
“When Scott showed me his photos, I said ‘Wow, this is quite amazing,’ ” said study co-author Alison Jones, a coral ecologist at Central Queensland University in Rockhampton, Australia.
Most of the previously documented cases of tool use in fish occurred in labs, Jones explained, and it was unknown whether fish used tools in the wild.
Other Tools, Other Users
1. Crows can craft twigs, leaves, and even their own feathers into tools.
2. Orangutans make whistles from bundles of leaves that are used to help ward off predators.
3. Elephants have been seen dropping logs or rocks on electric fences to short-circuit them.
4. Dolphins may carry marine sponges in their beaks to stir ocean-bottom sand and uncover prey.
5. Sea otters use stones to hammer abalone shells off the rocks and crack the hard shells open.
6. Gorillas have been known to test water depth with large branches.
7. Macaques living near a Buddhist shrine in Thailand are known to pull out visitors’ hair to use as floss.
8. Degus, small rodents related to chinchillas, were taught how to use rakes to find food.
Tooling Around, or Not
Not everyone agrees the shellfish-smashing fish is actually using a tool. “It’s taken six years to publish this research because reviewers argued back and forth about whether it was a true example of tool use or not,” co-author Jones said.
At issue is whether the tuskfish behavior fits the classic definition of tool use, which requires an animal to actually hold or carry the tool and use it to manipulate another object. But that definition was based on human and primate behavior, said Jones and her team, and can’t be applied to fish.
“We argue that tuskfish have a different type of intelligence that’s evolved for their specific environment … They don’t have hands, and they have resistance in the water, so you can’t expect them to use a tool the way a primate would.”
Fangs for Dinner
If scientists accept that tuskfish are indeed capable tool users, then it raises all sorts of interesting questions about fish behavior, the team says. For example, do the tuskfish use the same spot each time to crack open shellfish? If they do, it “adds weight to the long-held view that fish have a cognitive map and they can remember where to go,” Jones said.
It may be a while before the team has an answer. The behavior hasn’t been seen since 2006, but the researchers hope to catch a tuskfish in the act again soon. “We’re hoping to set up a camera at one of these sites at some point and get more information, but it’s technically demanding,” Jones said.
If tuskfish can use tools in the wild, then it’s possible other fish species can too—and that could have broader implications for fisheries management, Jones said. “If older fish are teaching younger fish these patterns of behavior, then by taking out all of the older”—and therefore bigger and more attractive to fishers—“fish, will the younger fish be less able to forage effectively?” Jones said. “That’s one of the critical questions that this observation raises.”
TRUTH:
WHEN A DOMINANT MALE TUSKFISH DIES, THE LARGEST FEMALE OF THE GROUP CHANGES SEX TO TAKE ITS PLACE.
SPEAK!
Piranhas Bark
Three Fierce Vocalizations Deciphered
If we could talk to the animals, the perusings of piranhas might be a bit one-note. Underwater microphones have picked up on their limited—and uniformly grumpy—“vocabulary.” So what are they saying?
Piranhas, it turns out, can be excellent communicators, a new study suggests. But don’t get the idea they’re going soft—their barks, croaks, and clicks likely mean “Leave me alone,” “I might bite you,” or “Now I’m really angry!”
“Eventually, if we understand the behavior that’s associated with the sounds, we might be able to listen to the sea and explain to fishermen: ‘Now’s not the best time to start fishing.’ ”
Eric Parmentier
lead researcher, University of Liège, Belgium, on deciphering piranha sounds
Fish Croaks
Researchers knew picking up red-bellied piranhas—among the few types dangerous to humans—could prompt croaks from the fish. Even so, no one had studied their sounds in water or provided good evidence for the barks’ evolutionary role.
Now a fish tank, an underwater microphone, and a video camera have helped uncover three different piranha calls—all tied to a variety of grumpy behaviors. “We knew piranhas were able to make sounds but were not satisfied with the explanation for how they do it,” said biologist Eric Parmentier of the Université de Liège in Belgium. “We wanted to know how they do this and what these sounds might mean to other fish.”
Grunts and Groans
Twenty-five species of piranhas exist in the wild today, but only “two or three” species pose a threat to humans, Parmentier said. In particular, the red-bellied piranha’s voracious appetite for fresh meat is a big reason many scientists have shied away from studying any in-water vocalizations, he added.
Parmentier and study co-author Sandie Millot of the University of Algarve in Portugal, though, used their tech-heavy technique to link three distinct sounds to three aggressive piranha behaviors. A repetitive grunt was tied to a visual face-off, as if to say, “G
et away from me.”
A second call resembling a low thud was associated with circling and fighting. Both of these calls, the researchers discovered, were made using a fast-twitching muscle that runs along a piranha’s swim bladder—an air-filled organ that helps fish maintain their buoyancy.
If fellow piranhas didn’t heed these warning calls, the aggressor would begin chasing the neighboring fish and making a third type of sound by faintly gnashing its teeth.
TRUTH:
PIRANHAS ARE OMNIVORES AND WILL EAT ALMOST ANYTHING, INCLUDING FISH, SNAILS, INSECTS, AQUATIC PLANTS, AND EVEN LARGER MAMMALS AND BIRDS.
Language Lessons
In the future, Parmentier and Millot would like to go to South America to record the red-bellied piranhas—and the other couple of dozen piranha species—in their native environment. “The nature of these fishes are quite special, and I suspect they can make more than three sounds,” Parmentier said, adding that they may also use them for hunting or mating.
“Also, there are only recordings for a few species of piranhas. We’d like to see what other species are capable of.”
HIT OR MISS
Squid Males Evolved
