There are too many wild horses out there. Here's why that's a problem for the West

The overpopulation of white-tailed deer is a conservation realization and an environmental disaster for the communities that harbor them. Hastings-on-Hudson, a progressive community, has opted for a humane birth control method PZP that is injected by darts into does. The method is successful for its non-lethal approach and the population growth has slowed, but as of yet has not significantly decreased.

Each year, close to three million dogs and cats are killed in shelters - in some cities more than 70 percent of the animals in shelters are euthanized. Target Zero is a program that works with fellow cities to spay and neuter animals and return them to the streets. Public complaints about animals have plummeted, and many shelters are well on their way to achieving a 'zero-kill' status.

Throughout the American West, recovering populations of wolves and grizzly bears have crept beyond the boundaries of national parks, clashing with sheep and cattle as they advance. Looking to Europe as an example, researchers are training and testing guard dogs in various western states as a means of deterring predators and protecting valuable livestock.

Veterans who suffer from post traumatic stress disorder number about one-fourth of military personnel returning from Iraq and Afghanistan conflicts, roughly 500,000 veterans so far. Inmates in prisons nationwide train dogs as companions for these war veterans, providing a sense of healing for all.

A robust population of grizzly bears can be an indicator of healthy land; however, the bears also can destroy grain bins, consume vegetation, and kill livestock. Ranchers work with the Canadian government and local conservation groups to protect their resources with bear-proof grain bins and electric fences.

As a state with robust populations of wildlife, Montana has had its share of roadkill. Its Department of Transportation developed animal shelving, a type of wildlife crossing, to enable safe passage for small animals who need to cross the road. The measure, combined with other types of crossings, has reduced animal-vehicle collisions by half.

Dutch farmers are saying no to antibiotics for livestock. The Netherlands is in the midst of a high-stakes, government-mandated experiment: Can large-scale meat production succeed without routine use of antibiotics?

Racing to contain the Zika outbreak, Brazil has deployed an army of health workers to eradicate mosquitoes. But in a country where standing water abounds, giving mosquitoes endless opportunities to breed, the task is daunting.

In different regions of the United States, beavers are considered a predatory pest and have been subjected to lethal trapping by Wildlife Services. However, Methow Valley in Washington has initiated a project that saves beavers by capturing them and taking them to places where they can help revitalize natural resources and the food chain. The Methow Valley Beaver Project has demonstrated that their efforts have provided effective against climate change and reshaping the land.

Ivory poaching has decreased the number of live elephants by one-fifth in the past decade. Although Kenya has ratified laws that make ivory poaching and trafficking punishable, identifying smugglers at border security is still a challenge. Airports in Kenya and Tanzania have employed dogs to sniff out ivory hidden in transit with a high success rate of 18 busts in four months at the Kenya location.