Smithsonian Science » mammals

Poachers at large in Thailand’s nature reserves despite ranger outposts

John Barrat — Fri, 11 May 2012 13:30:34 +0000

Khao Yai National Park in central Thailand covers some 1,357 square miles and, as Thailand’s oldest and most popular park, welcomes hundreds of thousands of visitors through its gates each year.

Recently, after examining hundreds of photos taken by camera traps set-up to monitor clouded leopards in the park, three Smithsonian researchers say Khao Yai also is quite popular with a different kind of visitor: poachers.

Next to the Eurasian wild pig, humans were the most common creature to show-up in the camera-trap photos, namely villagers, park staff, tourists and poachers, write Kate Jenks, JoGayle Howard and Peter Leimgruber of the Smithsonian Conservation Biology Institute in a recent issue of the journal Biotropica. Humans appeared in photos from 43 of the 217 different sites in the park where the camera traps were set, even though 78 percent of the park is zoned as a strict nature reserve/primitive area.

Images: Right, a clouded leopard in a camera trap photo. Above and below: poachers. (Photos courtesy of Kate Jenks)

Attached to trees in the forest, the camera traps use an infrared beam that can detect motion or a change in temperature to trip the camera’s shutter. The researchers considered humans in the snapshots to be “poachers” only if they were carrying a gun, a carcass or animal parts, a bag to carry forest products and animals; or if they were accompanied by a dog, Jenks explains.

Surprisingly, close analysis of the project’s some 650 photos revealed the presence of poachers very close to Khao Yai’s 21 ranger stations. Few carnivores, such as clouded leopards, were photographed near the stations.

“We expected to find higher carnivore biodiversity near the ranger outposts because those areas should be really well protected,” Leimgruber says. They are not.

In fact, Jenks says, “the ranger stations seem to be having the opposite of their intended effect. Building and staffing the outposts required the construction of roads into the park, which has provided easier access for everyone into the forest.”

This video depicts camera traps being set up in Thailand’s Pang Sida National Park, which is located adjacent to Khao Yai National Park.

In Southeast Asia poaching is fueled by demand from the traditional Chinese medicine trade, trade in wild bush meat for human consumption and forest products the researchers say. In addition, Jenks says, there are villages right up on the boundary of the park with no transition and no buffer zone. It is very easy for villagers to wander into the park.

Jenks, Howard and Leimgruber recommend increased foot patrols by park staff through the forest and continued monitoring of the impact of these foot patrols using the camera traps. Unless the human presence in and impact on the park is reduced, wildlife populations “will only shrink progressively into smaller and smaller core areas of the park” the researchers write.

(JoGayle Howard, a prominent researcher at the National Zoo who had dedicated her life to the study and conservation of endangered species, passed away last year. She had been instrumental in developing this wildlife conservation project.) –John Barrat

Article link: “Do Ranger Stations Deter Poaching Activity in National Parks in Thailand?” by Kate Jenks, JoGayle Howard and Peter Leimgruber appeared in the scientific journal Biotropica.

National Zoo gorillas participate in heart disease study

John Barrat — Thu, 26 Apr 2012 12:35:54 +0000

For a dentist, the narwhal’s smile is a mystery of evolution

John Barrat — Wed, 18 Apr 2012 16:33:32 +0000

When a dentist says “open wide,” he or she knows pretty much what they’ll find inside a patient’s mouth. But when a dentist peers into the mouth of an Arctic narwhal, all bets are off.

“Nothing makes sense,” explains Martin Nweeia, a practicing New England dentist and member of the Smithsonian’s Department of Vertebrate Zoology and the Harvard School of Dental Medicine. For one, narwhals have no teeth. “They eat large fish, yet swallow them whole. If you look in its mouth there’s nothing. There are absolutely no teeth.”

Image right: The mouth of a narwhal has no teeth. (Photo by Martin Nweeia)

Incredibly, the narwhal’s only visible tooth is outside of its mouth. Its tusk, in fact, is a giant canine tooth—that can grow as long as 9 feet—with a distinct left-hand spiral, covered in a tissue called cementum, normally only found around the base of a tooth lodged in bone.

Nweeia and a team of dentists and zoologists from the Smithsonian’s National Museum of Natural History, Harvard and other research organizations recently took a very close look at the dentition of the narwhal’s mouth. They studied more than 130 skulls in museum collections and 21 skulls of narwhals killed by native hunters in Canada. In a new paper published in The Anatomical Record, the team determined:

The long spiral tusk of the male narwhal is one of a pair of canine teeth positioned horizontally in the animal’s skull. They determined it was a canine and not an incisor because the tusk originates in the narwhal’s maxillary bone, where canine teeth in mammals originate. This is the first study to confirm the tusk as a canine tooth. In most mammals, canines are vertical in the mouth and are used for holding food or as weapons.

It is the left tooth of the pair that grows into a long tusk that erupts through the narwhal’s upper lip. The right canine tooth is also a tusk but it remains embedded in the narwhal’s skull unerrupted. Only occasionally do both tusks erupt. Female narwhals have two embedded tusks that erupt only very rarely.

Image left: A rare double-tusked narwhal in the collection of the National Museum of Natural History is examined by Martin Nweeia, left, and Charles Potter, collections manager, Smithsonian Marine Mammal Program. (Photo by Joseph Meehan)

A second pair of tiny teeth is located in open tooth sockets in the narwhal’s snout alongside the tusks. These teeth are vestigial, meaning they have no function. Close inspection across many specimens reveal extreme variation in location, morphology and histology (tissue structure) of these teeth, all indications they “are following a pattern consistent with evolutionary obsolescence,” the scientists write.

“It is striking when you think that this animal decided to take all of its tooth-producing energy and put it into one thing [a tusk] that sticks out nine feet into the ocean. With the amount of energy that it takes to produce that one tusk it could easily have 30 to 40 teeth in its mouth doing other things,” Nweeia explains. “Evolutionary-wise something is saying don’t do this, instead it is better to grow this extraordinary tusk.” A pretty compelling reason must be behind such a decision.”

Image right: An array of vestigial teeth collected from narwhals. (Photo by Joseph Meehan)

Did the narwhal once have teeth oriented vertically in its mouth as do other mammals? “One might assume this animal once had more teeth positioned vertically in the mouth, but there is no evolutionary evidence to say that would be true,” Nweeia explains. “With whales the evolutionary pieces of the puzzle are scant and I prefer to leave speculation out of the equation.”

There are many kinds of curious expressions of teeth in whales, narwhals being the most extraordinary, Nweeia says. “The strap-toothed whale, for example, has two teeth that wrap over its upper jaw preventing the animal from opening its mouth.”

Image left: The dissection team at the Osteo-Prep Lab of the Smithsonian’s National Museum of Natural History begins dissection on a male narwhal specimen. From left, James Mead, curator emeritus, Museum of Natural History; Ted Cranford, San Diego State University; and Martin Nweeia. (Photo by Chip Clark, Smithsonian Institution)

“The whole thing that is great about the teeth of the narwhal is that nothing makes sense,” Nweeia adds. “The tusks are an extreme example of dental asymmetry. They exhibit uncharacteristic dimorphic or sexual expressions since females do not exhibit erupted tusks as commonly as males. Also, the tusk has a straight axis and a spiraled morphology. Conventional mechanisms of evolution do not help explain these expressions of teeth.”–John Barrat

Article link: “Vestigial Tooth Anatomy and Tusk Nomenclature for Monodon monoceros,” The Anatomical Record, April 2012. Authored by Martin T. Nweeia, Frederick C. Eichmiller, Peter V. Hauschka, Ethan Tyler, James G. Mead, Charles W. Potter, David P. Angnatsiak, Pierre R. Richard, Jack R. Orr, and Sandie R. Black.

5 rabbit realities

John Barrat — Fri, 06 Apr 2012 12:06:24 +0000

In celebration of the annual spring appearance of the Easter bunny on Sunday, April 8, Smithsonian Science offers these facts from Rabbits: The Animal Answer Guide, a new book by John Seidensticker, conservation scientist at the Smithsonian’s National Zoo, and Susan Lumpkin, freelance writer.

1

Rabbits are not rodents, but lagomorphs (lag-uh-mawrf), a scientific term which means “hare-shaped.” Hares and pikas also are lagomorphs.

Image: A domestic rabbit, breed: Silver Fox (Photo by Mehgan Murphy)

2

Scientists studying the bones of an extinct giant rabbit found on the Mediterranean island of Minorca estimate this prehistoric animal weighed as much as 31 pounds! The largest rabbits alive today– domestic breeds such as the Flemish giant–weigh 22 pounds at most.

Image: A reconstruction of a giant Minorcan rabbit is shown next to a modern European rabbit. (Image by Meike Köhler)

3

Thanks to human introductions the European rabbit (Oryctolagus cuniculus) is found throughout Western Europe, Australia, parts of South America, North Africa and on more than 800 islands around the world. Today in Iberia, Spain, the European rabbit’s sole home for many thousands of years, it is threatened.

Image: A European rabbit. (Image courtesy Encyclopedia of Life)

4

Archaeologists have evidence of people hunting rabbits in the south of France some 120,000 years ago. Scientists suspect even Neanderthals lived on diets made up largely of rabbits.

Painting: “Der November” by Joachim von Sandrat (1606-1688)

5

A “never fail” Kansas folk remedy for reducing fever recommends making a strong tea from the dung of the wild jackrabbit and drinking it every half-hour.

Image: Black-tailed jackrabbit (Photo by Susan E. Adams)

Howler monkey born at National Zoo

John Barrat — Thu, 05 Apr 2012 10:26:59 +0000

Spring is in full swing at the Smithsonian’s National Zoo, and the Small Mammal House—which celebrated the birth of a black howler monkey (Alouatta caraya) March 22—is no exception. Since then, keepers have been monitoring the family at a distance, allowing first-time parents Chula (mother) and Pele (father) to bond with their baby.

The pair has exhibited strong parental skills and the young primate seems bright, alert, and increases its activity and independence day by day. This is the first surviving howler monkey in the Zoo’s history of exhibiting the animal. Its sex has not yet been determined. Zoo visitors can see the howler family on exhibit in the Small Mammal House.

Their thick necks house a unique voice box, including an enlarged hyoid bone, that enables male howler monkeys to penetrate three miles of dense forest with a single rumbling growl. These booming territorial calls have earned the primates, which are native to Central and South America, the title of loudest animal in the New World (North, Central and South America). The International Union for Conservation of Nature lists the black howler monkey as least concern.

Photos by Clyde Nishimura (top) and Janice Sveda, Smithsonian’s National Zoo

Heart disease study to benefit lowland gorillas at the National Zoo

John Barrat — Fri, 30 Mar 2012 15:03:34 +0000

The same device used to detect early warning signs of heart disease in humans will now benefit two male sub-adult gorillas at the Smithsonian’s National Zoo. Twelve-year-old Kwame and 10-year-old Kojo are the first western lowland gorillas (Gorilla gorilla gorilla) to participate in a study lead by the Great Ape Heart Project that will help veterinarians better detect and treat heart disease—the leading cause of death of male gorillas in human care.

Image right: Kwame in 2007 (Mehgan Murphy photo). Image below: Kojo in 2005 (Photo by Ann Batdorf); Image bottom: Kwame in 2007 (Mehgan Murphy photo)

On Feb. 2, Zoo veterinarians inserted an Implantable Loop Recorder beneath Kojo’s skin and between his shoulder blades. Kwame’s procedure took place on March 14. About the size of a USB drive, the ILR records electrocardiogram waves and allows animal care staff to analyze trends in the gorillas’ heart rates, rhythms, strengths and timing of electrical pulses.

“The Great Ape Heart Project is at the forefront of combating heart disease in gorillas, and we are honored to be one of the first institutions participating in this innovative research,” said National Zoo Director Dennis Kelly. “We hope that the information we learn will benefit this species and many others as well.”

Image left: Gorilla keeper Becky Malinksy trains Kwame to present different parts of his body, specifically his back, so that she can download data from the Implantable Loop Recorder.

Kwame and Kojo are ideal candidates for this study; they are clinically healthy yet the odds that they will develop heart disease later in life are high because of how common the disease is in gorillas. The Great Ape Heart Project chose them for another reason, as well: the Zoo’s training program allows animal care staff to monitor an animal’s health, administer medical procedures and provide preventive care without the use of anesthesia or restraints. Kwame and Kojo willingly present their backs to keepers Amanda Bania and Becky Malinsky on cue as part of everyday training. This ensures veterinarians will be able to scan the ILR, collect data and monitor trends in the gorillas’ health. The data will be shared among institutions and facilities that care for these primates. In addition, keepers will continue behavioral research projects and look for physical changes in Kwame and Kojo’s health.

“Even minute changes in their EKG waves could signal the onset of heart disease,” said Suzan Murray, chief veterinarian and head of the Zoo’s Department of Animal Health. “Detection is a major step in combating the disease.”

The notion of using ILRs in gorillas was first introduced by Dr. Ilana Kutinsky, co-director of the Great Ape Heart Project. As a cardiac electrophysiologist whose expertise lies in human medicine, she has seen ILRs save human lives.

“To ensure that these fascinating animals are around for generations to come, we must do everything possible to give them the best quality of life,” Kutinsky said. “Ultimately, this device will help improve great ape longevity in zoos.”

Kutinsky attended Kojo’s surgery and assisted Zoo veterinary staff. Murray and Kutinsky are two of the four scientists who have been at the forefront of gorilla heart disease for over a decade. The other doctors are Hayley Murphy and Pam Dennis.

In human care, western lowland gorillas can live to be upwards of 50 years old. In its native tropical forests of Western and Central Africa, however, a gorilla’s lifespan is about 35 years. Increased hunting, outbreaks of the Ebola virus and poorly regulated development projects threaten these great apes as well as their habitats. The International Union for Conservation of Nature lists the western lowland gorilla as critically endangered.

New fossil whale species raises mystery regarding why narwhals and belugas live only in cold water

John Barrat — Wed, 07 Mar 2012 04:05:01 +0000

A newly described species of toothed whale that lived some 3-4 million years ago during the Pliocene, is causing scientists to reconsider what is known about its living cold-water relatives: narwhals and belugas. These living marine mammals, ancient fossils show, have not always been the cold-water adapted creatures they are today, and why and when they evolved to live only in northern latitudes remains a mystery.

Bohaskaia monodontoides, as the new fossil whale is known, was recently described in a paper in the Journal of Vertebrate Paleontology by Jorge Velez-Juarbe of Howard University, who is also a Smithsonian predoctoral fellow, and Nicholas Pyenson of the Smithsonian’s National Museum of Natural History. This new species is known only from a nearly complete skull found in 1969 in a mine near Hampton, Va. Since its discovery, the skull has been housed in the paleontology collections of the Smithsonian’s National Museum of Natural History. It was loosely identified as belonging to a beluga whale but it had never been closely studied.

Image right: An artist’s conception of Bohaskaia monodontoides, foreground. Behind and above are a beluga and narwhal. (Artwork by Carl Buell)

In 2010, Velez-Juarbe and Pyenson began a close anatomical comparison of the fossil skull with the skeletons of belugas and narwhals kept in the collections of the Division of Mammals at the museum. Their study confirmed that the fossil skull was that of a new toothed whale species, one that shared features of the snout and face with belugas and narwhals. The fossil skull contained enough unique features however, to merit its placement as a new genus and species.

“Fossils referred to as belugas have been known from fragmentary bits, but skulls are so revealing because they contain so many informative features,” Pyenson says. “We realized this skull was not something assignable to a beluga, and when we sat down, comparing the fossil side by side with the actual skulls of belugas and narwhals, we found it was a very different animal.”

Image left: From left to right: Jorge Velez-Juarbe holds the skull of beluga whale; Dave Bohaska holds the skull of Bohaskaia monodontoides; and Nick Pyenson with the skull and tusk of a narwhal. They are standing in the marine mammal collections area of the Smithsonian’s National Museum of Natural History. (Photo courtesy Jorge Velez-Juarbe)

As Bohaskaia monodontoides was found in the temperate climate of Virginia, and a second extinct beluga-related toothed whale, Denebola branchycephala is known from a fossil found in Baja California, Velez-Juarbe and Pyenson surmise that the cold-climate adaptations of narwhals and beluga, which today live and breed only in the Arctic and sub-arctic, must have evolved only recently.

Image right: The fossil skull of Bohaskaia monodontoides. (Photos courtesy of Jorge Velez-Juarbe’s blog site Caribbean Paleobiology)

“The fact is that living belugas and narwhals are found only in the Arctic and subarctic, yet the early fossil record of the monodontids extends well into temperate and tropical regions,” Pyenson says. “For evidence of how and when the Arctic adaptations of belugas and narwhals arose we will have to look more recently in time.”

The change may be “related to oceanographic changes during or after the Pliocene affecting the marine food chain,” Velez-Juarbe says, “then competition or dietary preferences drove monodontids further north.”

(Bohaskaia monodontoides, was named in honor of David J. Bohaska, a museum specialist in the Department of Paleobiology at the Smithsonian’s National Museum of Natural History.)

Link to Dr. Nicholas Pyenson’s blog: http://nmnh.typepad.com/pyenson_lab/

Evolution of earliest horses driven by climate change

John Barrat — Mon, 27 Feb 2012 18:45:22 +0000

Paleontologists studying an extreme short-term global warming event have discovered direct evidence about how mammals respond to rising temperatures. In a study that appeared recently in the journal Science researchers from eight institutions including the Smithsonian’s National Museum of Natural History found a correlation between temperature and body size in mammals by following the evolution of the earliest horses about 56 million years ago. As temperatures increased, their body size decreased. Shown here are the are the teeth of the prehistoric horse Sifrhippus at its larger size (right) with teeth from the same species after its size shrank. (Photo by Kristen Grace, University of Florida.)

Wayne Clough & Carlos Jaramillo, at a research site near the Panama Canal.

John Barrat — Thu, 16 Feb 2012 18:31:09 +0000

Smithsonian Secretary Wayne Clough, left, talks with Carlos Jaramillo, scientist at the Smithsonian Tropical Research Institute in Panama, at a research site near the Panama Canal. Jaramillo and his team are collecting and examining prehistoric fossils exposed during the recent widening of the Canal. To date, they have discovered the fossils of a 12-inch-tall horse, a tiny camel, huge rhinos, turtles and trees 17- to 23-million-years-old. They have also uncovered evidence indicating the Isthmus of Panama did not emerge three million years ago, but as early as 22 million years ago. (Photo by Johnny Gibbons)

Is obesity predestined at infancy? Marmoset study may help scientists find out.

John Barrat — Tue, 14 Feb 2012 20:56:25 +0000

Childhood obesity is a serious concern, with more than 18 percent of American 4-year-olds considered obese. A new study of marmosets, small South American monkeys, indicates that obesity may begin very early in life and suggests that marmosets may be a helpful model for obesity in humans. In the study, scientists traced the difference between normal and obese adolescent monkeys to determine how much body fat they had at different ages during the first year of life. The findings were published in the March issue of the American Journal of Primatology.

“It seems like these animals are dividing into two groups at a very early age,” said Michael Power, a scientist at the Smithsonian Conservation Biology Institute’s nutrition lab based at the Smithsonian’s National Zoo in Washington, D.C. “It appears that developing obesity is something that can happen to an animal or a human before they have a real choice.”

Image right: Adult marmoset. (Photo by Michael Jarcho, UCLA)

Power is one of a team of researchers that studied white-tufted common marmosets (Callithrix jacchus) at the Southwest National Primate Research Center in San Antonio, Texas, from infancy through 12 months. The team found that fat marmosets, defined as those monkeys that ended the year with more than 14 percent body fat, also had more body fat at just one month old compared to monkeys that grew up to have normal weight. A 1-month-old marmoset is at about the same developmental stage as a human infant between 5 and 8 months old.

Image left: Baby marmosets cling to a stuffed toy. (Photo by Donna Layne-Colon, Texas Biomedical Research Institute)

Marmosets that ended up obese at one year could not be distinguished at birth from normal marmosets. Larger newborn marmosets did not necessarily grow up to be fat. However, the scientists did identify two risk factors that made marmoset obesity at one year somewhat more likely: an obese mother and access to high-fat food. This finding aligns with the results of previous studies of other species.

Marmosets serve as an appropriate model for obesity in humans because while most animals are born with little fat on their bodies, normal marmoset and human babies are quite fat at birth. A better understanding of obesity in marmosets, therefore, can help scientists identify risk factors, like a high-fat diet or an obese mother, and potential indicator measurements, like hormone levels or percentage of body fat, that could help identify a vulnerability to obesity in humans earlier.

From other unpublished results of this study, the researchers think the key may lie not in energy uptake, but in energy expenditure, the other side of the coin that makes up weight change.

“If I give you a sandwich, you’re going to store some of that energy as fat,” Power said. “Of course eventually you’ll use up that stored fat, especially if you are active and keep moving around. The problem comes when you consistently store more energy than you use. It’s a very simple idea, but the biology behind it is extremely complex. Unfortunately, many people and marmosets are better at storing fat than they are at remobilizing it and using it for energy.”

While the marmosets Power studies are fairly common, zoos are also home to other, more endangered monkeys, whose health and breeding potential could be crucial to their species’ continued survival. A better understanding of the development of obesity will enable zoo nutritionists to developed healthier diet plans for a variety of species. Visitors to the National Zoo can see Geoffroy’s tufted-eared marmosets, which are related to white-tufted common marmosets, in the Zoo’s Small Mammal House.

In addition to Power, the study’s authors are Suzette Tardif and Corinna Ross from the University of Texas Health Science Center at San Antonio and Jay Schulkin of the American College of Obstetricians and Gynecologists. The paper is available online.