Researchers based in the greater Yellowstone National Park area have found a new way to identify mountain lions-also referred as pumas- by using facial recognition. And it is proving to be effective to monitor these creatures that are highly elusive. "Mountain lions are really hard to directly observe." said Peter Alexander, a research biologist leading the research project. 

One tool they once used is a camera trap, which is attached to something along the animal's regular path. When motion is detected, the trap gets a shot of the mountain lion as it passes by. The cameras even have an infra-red (红外线的)flash for nighttime photos without disturbing the animal. 

Researchers around the world use this type of tool to estimate population numbers of species. But according to Alexander, there's a problem with this method when it comes to ID'ing mountain lions. 

All mountain lion around the world have light, sandy colored fur down their sides. The scientific name for a mountain lion, Puma concolor, literally translates to "one color". This lack of unique coloration (自然花纹)on the their body sides means researchers like Alexander can't usually tell if one puma crosses a camera trap five times, or if five individual animals pass by. 

However, it's a different story with their distinctive facial markings. Alexander and his team added some devices to their camera traps so that when motion was detected, a puma kitten call was played. This noise reliably attracted passerby pumas so that they looked up long enough for the camera trap to grab a shot for facial recognition. 

Compared to the traditional side angle camera trap, the new attention-getting device was about 92% more accurate. This work was recently published in the journal Ecology and Evolution. 

This study is an important step to being able to more confidently identify and track animals. Getting head images of mountain lions also opens up new opportunities to involve AI techniques. Alexander says that this new camera trap method could be used for tracking other wild animals that lack distinguishing side colors but have unique features elsewhere.

Before you worry about bacon and how much it may cost when new animal welfare laws go into effect next year, let's talk about the pigs that gave their lives for it.

California has been on the forefront of protecting animals who live short lives on factory farms either to produce food for us or to be slaughtered and sold as food. The latest advance came in November 2018, when 62.7% of the state's voters supported Proposition 12, the Prevention of Cruelty to Farm Animals Act. The law began going into effect last year, requiring hens and veal calves to be given more space to live in. Starting on Jan. 1st, the law will require that all eggs sold in California come from cage-free hens and that pork sold in the state come from breeding pigs that are not held in cages. These are humane steps designed to lift these animals out of structures that barely allow them to move.

Pork producers have had the longest time to comply (遵守). Some big companies like Hormel Foods have pledged to do so fully, but others have spent the last few years fighting the law rather than figuring out how to put it into practice. They say that the law will significantly raise the price of pork and that it violates the Commerce Clause of the Constitution, which gives Congress sole power over interstate business activity. So far, that fight has been a waste of time that pork producers could have better spent figuring out how to retrofit (翻新)their farms.

They also complain that the regulations on the law are not set. But the California Department of Food and Agriculture, which has yet to finalize the regulations, says that the delay should not have prevented producers from retrofitting their housing for breeding pigs. The agency has publicly posted draft regulations, which mostly concern record-keeping, certification and definitions of terms.

For fans of bacon and other pork, any rise in cost is the price of not having a pig suffer before it's killed for food. It's a price the animals shouldn't have to pay.

Amazing China in 60 Seconds is a short video series covering cultural and scenic hotspots across the country.

Tibet autonomous region in Southwest China, home to the highest plateau (高原) on Earth, is known as the "roof of the world". It's a paradise for tourists with its towering snow mountains, vast grasslands, peaceful lakes and breathtaking views. Must-visit places include the Potala Palace - a UNESCO world heritage site, Mount Qomolangma, Yarlung Zangbo Grand Canyon and more.

Tibet is also famed for its rich ethnic culture, including the Tibetan dance, age-old thangka painting and Lum medicinal bathing of Sowa Rigpa - traditional Tibetan bathing for a medical purpose which was included in the Representative List of the Intangible Cultural Heritage of Humanity by UNESCO in 2018.

Neighboring the Chinese capital city of Beijing, Tianjin rests between the northern Yanshan Mountains and the coastal plain. Adjacent to the sea and rivers, it carries distinct ecological beauty.

Tianjin is where Eastern and Western cultures meet. It has many precious historical sites, former residences of celebrities and foreign-style architecture. Famous tourist destinations include the Tianjin Eye, the Huangyaguan Great Wall, and the Five Big Avenues area, which hosts about 2,000 villas in various Western styles built in the 1920s and 1930s.

Southwest China's Chongqing is largely built on mountains and surrounded by rivers; thus it is known as the "mountain city". Many people are drawn to Chongqing by its delicious food - especially its signature spicy hotpot - and natural scenery.

Boasting the largest number of hotpot restaurants in China, Chongqing was named "China's Hotpot City" by the China Cuisine Association in 2007. Statistics show there are more than 50,000 hotpot eateries across the city. With more than 3,000 year of history, Chongqing still preserves traditional culture and lifestyles.