Mammals of the Sea

introduction:
Originally designed to live on land, marine mammals are a diverse, charismatic group of animals that include more than 120 species.

The animals share key characteristics of land mammals. They have hair, breathe air, give birth to live young, which feed off mother's milk when young. They have warm bodies and usually thick blubber to keep their body temperatures high.

Bottlenose Dolphin
The bottlenose dolphin is probably the most widely recognized marine mammal, easily spotted just offshore from beaches around the world. Small groups of 20 or less can live in close proximity to shorelines, but groups living more offshore can reach several hundred.

Bottlenose dolphin calves stay with their mothers for up to six years, learning how to hunt and become good dolphin citizens. Full-grown dolphins reach eight to 12 feet in length and can weigh up to 1,430 pounds.

The bottlenose dolphin is protected in U.S. waters.

humpback whales
What makes them "marine" depends on the animal. They either live mostly in the sea or, like polar bears, depend on the ocean for food.

The largest in the group are whales -- including humpback whales. These massive animals reach up to 50 feet in length and weigh up to 79,000 pounds. To maintain their weight, the animals feed on tons of krill and fish. They neared extinction due to whaling, but have recovered somewhat since a 1966 moratorium on whaling was introduce

Polar Bear
While polar bears live mostly on land or ice, they are excellent swimmers and have been known to swim up to 45 miles a day. The massive animals, weighing up to 1,500 pounds, hunt mostly seals.

In recent years, biologists have observed that the bears are swimming now more than ever as melting stretches the distances between Arctic ice flows. Because they depend on sea ice to hunt seals, the polar bear is considered threatened as global warming melts and thins ice in this region.

Sea Otter
This member of the weasel family is also the smallest marine mammal, with females weighing about 60 pounds and males weighing up to 90 pounds.

They may be small, but they're also clever. They're the only marine mammals known to use tools. They use stones to break open clams and store food they gather in the folds of their armpits!

Another feature that sets them apart is their lack of blubber. These marine mammals depend mostly on their fur to stay warm. That feature makes them particularly vulnerable to oil spills, which can compromise their fur's insulating effect.

Sea Walrus
mmediately recognizable by its long tusks and whiskers, the sea walrus is a hefty, flippered member of the Odobenidae family and is, in fact, the last living member of this group.

Since both the males and females have big tusks and not much for teeth, the animals feed by sucking up shellfish from the ocean floor.

So, just what are those tusks for? The longer they are (they grow to be up to four feet long in males), the higher an animal is ranked in the group. Males attack each other with their tusks to establish dominance.

The ivory appendages are also handy for poking holes in the winter ice and for helping the animals pull themselves out of the water.

Manatee
Manatees, also known as sea cows, are gentle herbivores that live in marshy areas in tropical and subtropical waters. The average adult manatee can weigh up 1,200 pounds and is around 10 feet long.

Because of their slow metabolism, these animals can only survive in warm waters. Due to the unusually long, cold winter this year in part of the southeastern United States, populations of manatees throughout Florida were devastated.

During the day, manatees usually like to stay close to the surface. At night, manatees will often sleep about three to 10 feet below sea level. This is why these gentle animals are so often accidentally injured, maimed or killed by passing boats.

Harbour Seal
Found up and down the North American coastlines, these marine mammals spend half of their lives swimming. Although they can reach up to six feet in length and weigh around 180 pounds, when on land and in plain sight harbor seals may not be easy to spot.

Their spotted brown or tan fur allows harbor seals to blend in with sand and rocks. Unlike their very vocal relatives -- sea lions and elephant seals -- harbor seals are quiet creatures that make little noise.

They like to hang out on beaches, sand bars and rocks during low tide to bask in the sun and sleep, but they never go far from the water. At the slightest sign of danger, they will quickly slip back under the waves. These expert swimmers have been known to plunge to depths of more than 1,600 feet and stay underwater up to 28 minutes.

Some Rare Species Found in 'Lost World'

May 17, 2010 -- A pristine New Guinea wilderness nicknamed "The Lost World" has just yielded multiple new animal species that seem more cartoon fantasy than flesh and blood reality.

The newly found animals, announced today by Conservation International, include a "Pinocchio" frog with a protuberance on the nose of males that points upward during energetic calls, but deflates and points downward when the males are less excited.

Other animals include a gargoyle-faced gecko, the world's smallest member of the kangaroo family, a huge, yet tame, woolly rat, a colorful pigeon, and dozens of other new species.

All were found in Indonesia's remote Foja Mountains on the island of New Guinea, an area that scientists first explored five years ago. The latest finds add to the dozens of new species already noted during that first trip.


'Pinocchio' Frog
Bruce Beehler, a senior research scientist at CI and a participant on both expeditions, told Discovery News that "to be able to return to this marvelous and pristine corner of the Pacific is a dream come true for field naturalists. After our 2005 visit, we knew there were more new species lurking in those mountain forests."

"Now that we can show how many unique forms live only there," he added, "it is easier for us to make the case that the world at large needs to take note and make absolutely certain that these superb forests are conserved for the wellbeing of the local forest peoples as well as the world at large."
No roads lead to the interior of the Foja Mountains, which rise over 3,281 feet and require a helicopter to access.

Paul Oliver, a University of Adelaide herpetologist who also went on the expedition, calls the new "Pinocchio" frog "one of the most remarkable frog discoveries" from the region "and clearly the most distinctive."

He said it was found "on a bag of rice in the campsite during torrential rain." He and his colleagues aren't sure what the function is of the frog's "bizarre nose."


Gargoyle-Faced Gecko
Oliver said the gecko is a new, large, bent-toed species that "could be found at night by its distinctive bright red eyeshine."

Since the species often spends time high in the woodland canopy, it required "some rather risky acrobatics" to study. He and his colleagues hope to publish a formal description of it by late 2010 or early next year.


Gentle Wallaby
Kristofer Helgen, curator of mammals at the Smithsonian's National Museum of Natural History, described four other animals found in the Foja Mountains.

He said the smallest member of the kangaroo family is a "diminutive dark-furred forest wallaby." Helgen added that it's "a gentle inhabitant of the mountain forests of this isolated mountain range."

Unlike most mammals there, the wallaby is active during the day. As a result, many members of the expedition team reported seeing it as they went about their work.


Woolly Rat
Helgen said the new woolly rat weighs more than 3 pounds. Despite its formidable size, it "was rather tame," spending much of its time foraging at night on the forest floor.

Delicate Tree Mouse
Helgen described the new tree mouse as being a "delicate herbivorous mouse" that "scurries along tree branches and vines during the night in search of its favorite foods."

Blossom Bat
Helgen also described a new blossom bat, a tiny species "that feeds on nectar at the flowers of rainforest trees."

'Strange' Pigeon
Ornithologist Neville Kemp helped to document the "strange pigeon," with rust, white and gray feathers. He spotted a pair of these new birds as they were "being entirely distracted by the courtship display and mating of Foja's endemic golden fronted bowerbird that was taking place before their eyes."

Were it not for this bit of bird voyeurism, Kemp might not have made the discovery.

Other species recently found in the Foja Mountains include a new flowering shrub, a new black-and-white butterfly related to the monarch, and at least 11 other new insects.
Beehler and his colleagues hope their work will encourage the government of Indonesia to bolster long-term protection of the area, which is today classified as a national wildlife sanctuary.

"Places like these represent a healthy future for the Earth," he said.

Predators Pick Body Parts for Balanced Diet

Many meat-eating insects and animals, including humans, selectively feed on certain body parts to balance their nutritional intake, says a new study.
“Would you like a leg or some breast meat?” may not be a life-or death-question for people sitting around a dinner table topped with other goodies, but for predators like spiders and wild cats that repeatedly eat only one or two different species, the decision could be the difference between keeling over or living to enjoy another meal.
The study, accepted for publication in the journal Animal Behavior, is the first to demonstrate how specialist carnivores achieve a balanced diet by choosing to eat certain body parts and leave others behind. These choices are probably driven by hunger pangs.
For ant-eating Zodarion spiders, the focus of the study, such pangs might compel them to eat an ant head, leg or gut.
Stano Pekar, lead author of the study, told Discovery News that since the spiders “are choosy about the various body parts, we assume that they get something like hunger cravings for specific nutrients. It has been shown previously for other predators, including spiders, that they select different types of prey or food according to their nutritional needs.”
Pekar, a researcher in the Department of Botany and Zoology at Masaryk University, and his colleagues collected Zodarion spiders -- a tiny and rarely seen nocturnal arachnid -- from various places in Brno, Czech Republic.
The first tests within the study were like mad scientist cooking experiments. The researchers prepared and nutritionally analyzed different ant meals for the collected spiders. These meals consisted of whole ants, just the gasters (the bulbous-looking main body part), or the heads and appendages. The scientists then analyzed the choices spiders made when feeding on whole ants, and what the spiders’ survival rate was over the study period.
The spiders' survival was significantly affected by which body parts they fed on. The spiders that had to eat entire ants fared worse than spiders that were able to pick and choose ant parts. That’s probably because each of the ant parts provides different nutrients. The legs have a lot of nitrogen, the head has more protein and the gaster is “fattier,” with more calories.
Ants may protect their gaster “because it contains defensive chemicals, such as formic acid,” Pekar said. That doesn’t completely stop spiders from eating it, but the acid makes the gaster less appealing to spiders.
The findings about selective body part feeding apply to certain other spiders, insects and animals, especially those that eat just a handful of species, according to the scientists.
“Felid cats, such as cheetahs or lions, are often restricted in their diet because they catch mainly gazelles (in the case of cheetahs) or zebras (lions), so these game cats can also select only certain tissues from the entire prey animal. They can exploit only muscles if they need proteins, or fat reserves if they need lipids,” Pekar said.
Although most humans have access to many different types of food, a study conducted at Tufts University found that we tend to crave high-calorie items.
“Energy-dense foods, such as chocolate and some salty snacks, are those that pack the most calories per unit of volume, as compared to less energy-dense foods like fruits and vegetables, which have fewer calories per unit of volume,” explained Cheryl Gilhooly, a research dietician who led the study.
As a result, most of us tend to crave things like French fries over steamed broccoli. When our bodies change, however, the cravings can change too.
“This is quite apparent in pregnant women who have a very strong preference for certain types of food at various stages of their pregnancies,” Pekar said. “I assume that they need to supplement certain nutrients for the development of the baby.”
For people who want to lose weight, Gilhooly and her team advise that it’s best to not try to suppress cravings. Instead, don't give in to them, or substitute foods that taste similar, but have fewer calories.

Oil Spill Threatens Gulf Seafood

Gulf Coast fishermen are hustling to harvest shrimp, oysters and fish before the environmental disaster gets any worse. For shrimp- and oyster-lovers, the message is keep on eating -- at least for now.
Seafood industry officials say it's too early to tell whether the summer catch will end up being a disaster, or merely a setback.
"Our brand has been damaged severely, but we still have significant fisheries operating," said Ewell Smith, executive director of the Louisiana Seafood Promotion and Marketing Board. "Our biggest challenge is letting consumers know we still have 70 percent of our fisheries open. The seafood is safe and the fish and waters are being tested."
Two-thirds of the oysters eaten in the U.S. come from Gulf coast states. As of Wednesday, officials said the slick was nine miles from Pensacola, Fla., and moving toward the productive oyster beds of Apalachicola Bay, Fla.
Federal officials have closed more than one third of the Gulf of Mexico to fishing operations, mostly in the eastern side of the Mississippi River Delta. State wildlife officials also closed about 125 miles of Louisiana's coastal oyster beds as oil has polluted wetlands and shallow bays where these shellfish thrive.
For shrimpers, the good news is that the oil has stayed away from the larger fishing grounds east of the Mississippi toward Texas.
"The areas that are the largest and most productive have not been affected by the oil spill," said Roger J. Zimmerman, director of NOAA's Southeast Fisheries Science Center in Galveston, Texas. "We won't know the long-term effects on the fisheries until we do monitoring and assessment to tease out the effects of oil and the normal environmental affects."
Americans eat more than four pounds of shrimp per person each year, topping the list of favorite seafood. But only 7 percent comes from the Gulf of Mexico. The rest is imported from Southeast Asia and Ecuador, according to the National Fisheries Institute, a trade group.
"We like to think that wild caught shrimp from (the Gulf) are much better than pond-raised shrimp from Asia," said David Veal, head of the American Shrimp Processors Association in Biloxi, Miss. "If we were to stop the flow and clean it up, we might escape with minimum damage."
Still, there are growing concerns about the perception of restaurateurs and at-home cooks. Industry representatives say that it took nearly two years for U.S. consumers to return to Gulf seafood after Hurricane Katrina.
Already some seafood restaurants are saying no to Gulf shrimp, even though no contaminated seafood has turned up.
"They need to get it capped," said Harlon Pearce, chairman of the Louisiana seafood board, about the BP well. "Nobody can feel comfortable with an oil spill."
Eric Niiler is a freelance writer based in Washington, D.C.

Telescope in the Sky Makes Debut Flight

An infrared telescope designed to study star formation, extrasolar planets and other celestial phenomena opened its eye on the universe for the first time Wednesday, from a vantage point 35,000 feet above ground.
The Stratospheric Observatory for Infrared Astronomy, or SOFIA, took off from Palmdale, Calif., shortly before 1 a.m. EDT for an overnight trial run, the culmination of a 13-year development effort led by NASA and the German Aerospace Center.
"Everyone is all smiles," said Nicholas Veronico, with the Universities Space Research Association, which operates the observatory for NASA.
The 2.5-meter telescope -- three times larger than NASA's infrared Spitzer Space Telescope -- is mounted into a modified Boeing 747 jet that is expected to fly two- to three times a week for the next 20 years.
Operating at 45,000 feet -- above most of Earth’s infrared-absorbing water vapor -- SOFIA is nearly as capable as a space-based telescope, without the launch costs. It also can be easily upgraded with a variety of science instruments, outfitted for several different types of studies and flown to view particular targets.
"We're 80 percent of a space telescope and yet we come home every morning," astronomer Dana Backman told Discovery News.
For first light, the telescope was outfitted with an infrared camera designed and built by scientists at Cornell University. Seven other instruments are in various stages of completion and expected to be ready by this fall, Backman said.
The instruments will take turns flying on SOFIA, during observation runs spanning three- to five flights each.
Wednesday's flight was intended to calibrate the instrument and assess SOFIA's capabilities. The telescope is sensitive to light radiating in a broad range of wavelengths from ultraviolet to microwaves. The telescope's sweet spot is the infrared region, where objects basically cooler than stars emit most of their energy.
Like many ground-based observatories, scientists can work on-site, though for SOFIA's studies, that means hopping aboard the aircraft for a night in the sky. The aircraft has seating for about 15 people.
"Astronomers are kind of old-fashioned. They like to be there in the chair when the observing is going on," Backman said.
Though not as sensitive as Spitzer, SOFIA can make out finer details and is sensitive to a broader spectrum of light.
Scientists plan to use SOFIA to study star formation in the Milky Way and other galaxies, hunt for organic molecules in space and pick apart the chemical composition of extrasolar planet atmospheres.

New Dinosaur Had Record-Sized Horns

A newly discovered five-ton dinosaur has the largest horns ever found on a dinosaur, with a set that were 4-feet-long each, according to paleontologists who unearthed the hefty herbivore in Mexico.
The name of the new species, Coahuilaceratops magnacuerna, translates in part to "great horned horny face," and the dinosaur lives up to its description. In addition to the two enormous horns above each eye, it also had an unusual, rounded nose horn not seen before on any other dinosaur.
"The large horns certainly would have been heavy to haul around, but we know from related animals that horned dinosaurs had very large neck muscles to take care of this problem," project leader Mark Loewen told Discovery News.
Loewen, a paleontologist at the Utah Museum of Natural History at the University of Utah, and his colleagues recovered the new ceratopsid (horned) dinosaur in arid, desert terrain within the Mexican state of Coahuila. When the dinosaur was alive 72 million years ago the region was a humid estuary with lush vegetation.
Based on the dinosaur's remains, the researchers believe that it was rhinoceros-sized -- about 22 feet long as an adult, 6 to 7 feet tall at the shoulder and hips, and with a 6-foot-long skull. Both males and females of the four-legged, plant-eating dinosaur had the massive horns, which were probably used to attract mates and to fight with rivals of the same species.
Although the dinosaur looked somewhat like a rhino, the horns were very different. Rhino horns are made of soft tissue, while Coahuilaceratops horns had a bony core surrounded by soft tissue, similar to the horns of modern sheep, goats and cattle.
Loewen said that "based on the position and orientation of the horns, it might have engaged in 'horn locking' as seen in some modern three-horned chameleons."
The new species will be announced in the book "New Perspectives on Horned Dinosuars" to be released next week by Indiana University Press.
In addition to this dinosaur, the researchers found the remains of possibly five or more other new dinosaur species. Two were duck-bills, and one of those has already been named Velafrons coahuilensis.
They also found another horned dinosaur and the remains of carnivores, including large tyrannosaurs that were smaller, older relatives of Tyrannosaurus rex, and more diminutive Velociraptor-like predators armed with sickle-claws on their feet.
While exploring the region, the paleontologists noticed large fossil deposits with jumbled dinosaur skeletons, suggesting that mass death events occurred at the site, possibly due to hurricanes and other storms that occur there today.
"We know very little about the dinosaurs of Mexico, and this find increases immeasurably our knowledge of the dinosaurs living in Mexico during the Late Cretaceous," Loewen said, adding that "Mexico's dinosaurs have been elusive, in part, because many areas there are so remote, and partly because there are so few paleontologists in Mexico who study dinosaurs."
From about 97 to 65 million years ago, high global sea levels resulted in flooding of the central, low-lying portion of North America. As a result, a warm, shallow sea extended from the Gulf of Mexico to the Arctic Ocean, splitting the continent into eastern and western landmasses.
Central America had not formed at the time, so Mexico was the southern tip of an island continent. Western North America was connected to the region, so the dinosaurs of Mexico were most closely related to species from there. Mexico's dinosaurs were less similar to those in South America, since the sea served as a large barrier between the two areas for much of the Cretaceous.
Don Brinkman, a researcher at the Royal Tyrrell Museum who studies early non-dinosaur vertebrates from Mexico, said, "Dinosaurs from this particular period are important because this is a time that is relatively poorly understood."
He added, "The locality in Mexico goes a long way to filling in a gap in our knowledge of the record of changes in dinosaur assemblages throughout the Late Cretaceous."
Coahuilaceratops specimens are currently on exhibit at the Museum of the Desert in Saltillo, Mexico. The horned dinosaur's skull will be unveiled at the museum later this year.

Animal Screams Manipulate Movie Audiences

From screaming meerkats to roaring lions, animal distress calls and other animal vocalizations are being included, or copied by instruments, in film soundtracks to influence human emotions on a primal level.
The musical manipulation works because humans and other vertebrates are predisposed to be emotionally affected by animal yells, human baby cries, and other noises that may sound harsh and are unpredictable, according to a new study published in the latest Royal Society Biology Letters.
As a result, snakes, lions, hippos, birds, whales, dolphins and even fish are now being recorded for film soundtracks, or are being emulated by musicians. In the future, more such sounds will likely be included in movie scores, which will probably do a better job at influencing audience emotions since the science behind the process is coming to light.
Daniel Blumstein, who co-authored the new study, told Discovery News that "our results suggest that good composers and those putting the entire soundtrack together are tapping into a common mammalian, and probably avian, phenomenon -- that certain types of sounds evoke certain sorts of emotions."
Blumstein, who is chair of the Department of Ecology and Evolutionary Biology at UCLA, added that composers are "tapping into our mammalian roots to evoke fear, a basic emotion. Everyone knows what a really upset dog sounds like, versus one just barking, and everyone knows what a fear scream sounds like. These (distress calls) are remarkably conserved among mammals and in birds."
He and colleagues Richard Davitian and Peter Kaye heard plenty of screams, shrieks, wails and other fear-inducing sounds after analyzing the soundtracks for 102 films from four genres: adventure, dramatic, horror and war. Choices were based on Internet film sites' public polling lists of the best films within these categories.
The researchers determined that the soundtracks for each film genre possessed characteristic emotion manipulating techniques. The scores for dramatic films, for example, had more abrupt frequency shifts, both up and down, to induce emotional changes in moviegoers.
Horror films, on the other hand, usually had screaming females, while adventure films incorporated a lot of noisy male screams into their soundtracks. War movies had more fluctuations in volume than expected.
While humans often served as the soundtrack screamers, the researchers detected non-human animal sounds in many films.
"From sound editor Murray Spivak's groundbreaking work on "King Kong" (1933) right until today, including films such as sound designer Christopher Boyes' "Avatar" (2010), the basic material of many film sound effects start with real, recorded biological animal vocalizations," said Kaye, who is himself a musician and composer for television and film.
He added that usually these people "can often be found at zoos with their portable recorders and headphones on."
This latest study was even inspired by Blumstein's field studies on marmots. While looking at acoustical features of marmot pup screams, he discovered that some characteristics were difficult to measure because they were filled with nonlinear elements. He later determined that virtually all mammal screams shared these harsh, rough and unpredictable qualities.
"I then did some experiments with marmots and found that adding noise to adult alarm calls made the calls scarier," Blumstein said.
Electronic manipulation of such sounds is just one technique that composers use to create the nonlinear noises that can whip audiences into a state of suspense or fear, according to the researchers. Other methods include having brass and wind instrument players over-blow, or directing violin players to rapidly move their bows across the strings without losing contact with their instruments.
The more extreme these sound effects are, the better the audience response seems to be, indicated Kaye.
"As any of us movie lovers well know, when confronted by the supernatural, gigantic, or just plain nasty and gnarly, we humans will express our immediate emotions with passion and vigor," Kaye said. "It seems that all of us vertebrates do it!"