The Beagle Brigade

Return to the United States from a trip abroad, and your luggage will get inspected by the U. S. Department of Agriculture’s Beagle Brigade. Working with human canine officer partners, the beagles sniff out potential threats to American agriculture.

An orange or apple, for example, might harbor a Mediterranean fruit fly. Hams could carry a disease such as hog cholera. These and other pests could destroy farmer’s crops and livestock. “Once we introduce something that is not part of the environment, there may riot be any controls for it in the environment,” notes USDA’s Lisa Davis at the National Dog Detector Training Center in Orlando, Florida. “The best thing for us to do is to prevent it from coming across the border and becoming established. ’’

When a beagle sniffs specific food odors, it signals its partners by sitting. The human officer then investigates. When the dog is right—which happens 90 percent of the time——it gets an edible treat.

“The dog is not out there working,” explains Davis. “It’s out there playing. It’s a game to the dog.” The handlers give the beagles plenty of food and loving. They make sure they get first-class medical attention, too. When the dogs finally retire after 9 to 11 years, the USDA finds caring homes for them. It’s a dog’s life indeed!

How well does the Beagle Brigade do its job? “On average,” notes Davis, “each year our 54 teams prevent around 75,000 prohibited, restricted items.” Since even one infested (为患的) item could cause widespread destruction, that’s a great result for America’s agricultural environment.

Madagascar’s extremely improbable wildlife may be thanks to dozens of dramatic oceanic journeys that would put Robinson Crusoe to shame, says a new research.

“It seems like a far-fetched idea that animals could survive moving across the sea,” says Matthew Borths, a researcher at Duke University. But a comparison of genetic data from modern Malagasy species with the fossil (化石) record of their ancestors from the African mainland has revealed that this is likely what happened for most land animals, according to the research, published in May in the journal Biological Reviews.

Animals from mainland Africa would have been trapped on large rafts (木筏) of vegetation and floated to Madagascar, where they eventually evolved (进化) into the wildlife we know today. Some 95 percent of wildlife are endemic to the country, which means they live nowhere else in the world.

Scientists have three major theories to explain how land animals got to Madagascar: The species were there before Madagascar divided and became an island, they swam and/or rafted across from mainland Africa when currents flowed that way, or they crossed land bridges that might have existed at different periods.

In their study, Jason Ali, the study co-author, and Blair Hedges, a biologist at Temple University, pulled together a large amount of previously published research to test each of these possible origin stories.

The team compared the genes of 28 groups of land animals, including animals from modern-day Madagascar, with the genes of species on mainland Africa that are the closest, relatives. Based on this information, they calculated the likely time when the ancestor of each species group likely arrived in Madagascar, then evolved into something new.

As our boat moves quickly up and down in a windy ice-filled small bay, I try to judge the health condition of the polar bear (北极熊)in front of me. We are in Franz Josef Land, a remote part of Russia between the Barents Sea and the Arctic Ocean.

While offshore bears follow the sea ice, hunting seals (海豹)on ice all year round, bears that live by the sea spend their summers on land and are forced to search for whatever they can find. Relying on low-calorie meals such as the eggs of nesting seabirds, it is harder for these bears to pack on the pounds. Researchers recently found that offshore bears around the Barents Sea are some of the most polluted animals on Earth. This is a direct consequence of the seals they feed on.

Over a period of 14 years' study, Heli Routti from the Norwegian Polar Institute found that offshore female bears were in a better health, having greater body weight, than female bears by the sea, but on average their levels of pollutants called PFASs are 33 percent higher.

PFASs are used to make industrial products which are poisonous and degrade (降解)very slowly. These pollutants find their way to the Arctic through air, where they fall in snow and gradually add up in the ice. As the ice melts every summer, the PFASs go into the water, where they enter the food chain. They eventually make their way into the fat that keeps seals warm and from there into the bears that eat them.

During my 15 days in Franz Josef Land, I saw five bears, all living by the sea. Each looked relatively healthy. There are signs that these bears are dealing with the global-warming-caused ice loss relatively well. “The bears, so far, seem to be handling the sea ice loss,” says Andrew Derocher at the University of Alberta, who worked with Routti on the study, “But I'm sure that's going to change if the speed of ice loss increases sharply in the area.”