When bears, wolves and foxes are your only neighbors, life can be pretty lonely. Add minus-60-degree days and a constant battle for the most basic necessities, and you have the daily challenges of people who live in remote corners of Alaska. This series takes viewers deep into an Alaskan winter to meet tough, resilient residents as they try to stay one step ahead of storms and man-eating beasts to survive the season. The closest neighbor to Sue Aikens is more than 300 miles away. Eric Salitan subsists solely on what he hunts and forages. Chip and Agnes Hailstone catch fish for currency in bartering for supplies, and Andy and Kate Bassich use their pack of sled dogs for transportation. Also highlighted is a time of year not always part of what viewers see in Alaska: spring! Ice is breaking, animals are waking, and residents face new tests before deep cold returns.

Combining feature film-quality scripted elements and visual effects with documentary-style interviews, "Mars" illuminates the peaks and valleys of a modern-day space race while dramatizing humanity's first harrowing attempt to colonize the distant planet. The scripted portion is told from the point of view of a maiden Mars mission in 2033. Led by commander Ben Sawyer, the crew of the Daedalus spacecraft must overcome monumental obstacles if it is to successfully establish the first sustainable colony on Mars. Oscar and Emmy winners Ron Howard and Brian Glazer, via their production house Imagine Entertainment, are among the series' executive producers, and visionary Mexican filmmaker Everardo Gout ("Days of Grace") directs.

In the varied forms of veterinary medicine, Dr. Susan Kelleher's practice may be one of the more unusual. Known as Dr. K, she runs South Florida's Broward Avian and Exotics Animal Hospital, and this series follows the staff as it cares for rabbits, ferrets, foxes, fish, birds, reptiles, marsupials, and even primates. As do some other vets, Kelleher thinks domesticating wild animals like monkeys is a bad idea, but that feeling doesn't interfere with her taking care of them: "If it will fit through the door, I'll treat it," she says.

Put up your dukes -- er, paws -- and prepare to discover epic, bone-shattering clashes between some of the world's deadliest predators. From lions, tigers and bears to meerkats, mongoose and mice, the series features testosterone-induced battles between some of the biggest, baddest and often surprising fighters in the animal kingdom, revealing the extraordinary motivations and strategies that fuel each incredible brawl.

"Lockdown" plunges viewers headfirst into life in the "big house," the gritty underworld of America's maximum-security prisons, where gangs are prevalent, predators stalk their next prey and inmates are armed with deadly weapons. But prison officials have their own weapons in the form of modern surveillance and old-time isolation -- plus steel batons and pepper spray -- to help keep the peace in these miniature war zones.

Patrolling America's largest state is the job of roughly 400 troopers in one of the toughest law enforcement agencies in the nation. Essentially, these cops say, nearly every Alaskan resident is armed and they know how to use their weapons, which makes any scenario a trooper encounters a potentially fatal one. Follow along as the "blue shirt" Alaskan State Troopers police the towns and villages, and the "brown shirt" Alaska Wildlife Troopers enforce regulations covering both commercial and sport fishing and hunting activities.

Making house calls in the far reaches of Northern Canada is a daunting task in the least, considering the houses may be separated by hundreds of miles. That challenge doesn't stop Dr. Michelle Oakley from performing her many duties as a veterinarian in one of the most rugged environments on Earth. In addition to running an animal clinic out of her home in Haines Junction, Yukon -- where she lives with husband Shane and their three daughters -- Dr. Oakley also operates a satellite clinic 150 miles away and is the on-call vet for the Yukon Wildlife Preserve, which is about 100 miles from Haines Junction. She also makes house calls, sometimes driving for long stretches through desolate wilderness to check on a patient. This series documents how Dr. Oakley juggles being a full-time vet, wife and mom, and does so with a sense of humor and devotion.

Consistently stunning documentaries transport viewers to far-flung locations ranging from the torrid African plains to the chilly splendors of icy Antarctica. The show's primary focus is on animals and ecosystems around the world. A comic book based on the show, meant to be used an as educational tool for kids, was briefly distributed to museums and schools at no cost in the mid-2000s.

Five individuals leave their mainstream lives behind to face the challenges of life in the wild.

Unlocking ancient Egypt's greatest mysteries.

"Have vet, will travel" isn't printed on his business cards, but it succinctly describes Dr. Bartholomew Buckeye Bottoms' dedication to serving hundreds of clients across Hawaii who depend on his mobile veterinarian practice. Since 2007, Dr. Bottoms has delivered life-saving treatment to sick animals large and small on the islands of Maui, Lanai, Molokai, Oahu, the Big Island, and Kauai. As seen in hourlong episodes of this reality series, Buckeye prides himself on going where other vets won't -- with his truck as his office, and faithful canine companion Kevin always by his side. Buckeye, by the way, is the son of actor Timothy Bottoms.

This award-winning series presents compelling untold stories and covers a wide array of provocative subjects. "Explorer" aired for 25 years -- the longest-running documentary series in cable TV history -- before being relaunched in 2015 after a five-year hiatus. Each monthly episode of the new "Explorer" takes a similar deep dive inside a story from the pages of a recent National Geographic magazine issue, taking viewers not only to the most remote corners of the globe but also to the furthest reaches of the mind and deepest crevices of history -- on urgent missions of discovery.

From the Arctic Ocean and its isolated Islands to the bleak, barren tundra and frozen forests of the taiga, the Arctic region is locked in ice for more than half of the year; in summer, this land of contrast bursts into life.

The wilderness of Yellowstone Park.

Cameras follow the action along Arizona's Sonoran Desert, one of the busiest border crossings in the country, as officers and agents of U.S. Customs and Border Protection fight terrorism, apprehend drug smugglers and intercept people entering the United States illegally. The series also embeds with Customs and Border Protection, and with local law enforcement, as units patrol near and on the border in South Texas.

National Geographic Channel turns its state-of-the-art cameras on America for a close-up of its national parks. More than three years in the making, the eight-part series goes beyond the homegrown beauty to allow viewers to witness moments full of drama, watch stories of life and death, and discover hidden gems in high-tech ways heretofore never presented on TV. Each hourlong episode features one park, from the geysers of Yellowstone and the hot desert of Saguaro to the sprawling Smoky Mountains and world-famous Grand Canyon.

The daily and subsistence activities of the inhabitants of the most frigid areas on the planet.

Houston's Gulf Coast Veterinary Specialists is one of the country's busiest animal hospitals, with a staff that treats more than 50,000 patients annually. "Animal ER" brings cameras inside the facility to show viewers what goes on as the veterinarians and other staffers treat their beastly patients. The animals that are treated range from typical pets like dogs and cats to more exotic creatures like chimps and pythons.The staff uses state-of-the-art technology while working in such disciplines as surgery, internal medicine, oncology, dentistry and dermatology.The partners at GCVS include orthopedic surgeon Dr. Brian Beale, who performs 10-20 surgeries per week, and surgeon Dr. Heidi Hottinger, who has done everything from removing cancerous tumors to performing amputations.

Africa is home to some of the deadliest creatures of all, and in this series, you'll see them.

How does the drug trade work? Can it be stopped or should it be regulated? And what are the personal costs? Those are just some of the questions asked in this series, a comprehensive look at society's most abused drugs: cocaine, methamphetamine, heroin and marijuana. First-person perspectives from traffickers, dealers, users, law enforcement and medical professionals detail how the drugs are processed and moved onto the streets, and the effects they have on the human body. It's a raw, eye-opening documentary about a billion-dollar industry.

Dr. Jan Pol has been a practicing veterinarian for more than half his life. In 1981 he and his wife, Diane, opened a vet business out of their home, and over the years it has grown to service more than 19,000 clients. Set in Central Michigan's farm country, this reality series follows the work done at Pol Veterinary Services. Specializing in large farm animals, Dr. Pol treats horses, pigs, cows, sheep, alpacas, goats, chickens and even an occasional reindeer. The program also features Dr. Brenda Grettenberger, who has worked with Dr. Pol since 1992.