Pet overpopulation: Too many pets and animals are dying because of it.
An estimated 4 million homeless dogs and cats are euthanized each year in the United States, more than 10,000 in Tulsa alone.
Finding them homes is Dan Canfield's top priority. He's the adoption manager for the Humane Society of Tulsa.
"That's just the greatest feeling," said Canfield. "You get to see animals that go home."
But you could say it's his "day job."
Several times a year, in the middle of the night, Canfield and the HST founders load up dozens of puppies. At times 75 in a single trip, but a thousand animals over a year and a half.
The puppies are taken to the Humane Society of Boulder Valley. Boulder has no population problem. They have the unheard of: Extra space.
The Boulder Humane Society takes in truckloads of puppies every week from 32 shelters across the country, including Humane Society of Tulsa and the Washington County SPCA.
About 2,800 animals were transported in 2011 alone.
Boulder CEO Lisa Pedersen contributes success to an aggressive spay and neuter program, a strong commitment from residents and partnerships.
"The collaboration across the state between agencies and rescue groups and municipal shelters to ensure working together we can save the most amount of lives," said Pedersen.
She says it took about 10 years to get the pet population under control.
Currently, fewer than half of the animals at Boulder Valley are from the Boulder area.
Transported animals are generally adopted within six days of their arrival.
Humane Society of Tulsa founder Hank Johnson says there is progress here.
"Tulsa's coming along," said Johnson. "I've been in animal rescue for 10 years and we're getting better."
HST is working to offer more low-cost spays and neuters.
City ordinances require all dogs and cats over the age of six months to be spayed or neutered. Some exemptions are allowed by permit.
The group also rescues animals from the local shelter on a weekly basis.
The one major obstacle that made Boulder successful may prove the most difficult to overcome.
"The problem is changing the mindset of the community," said Johnson. "The mindset of 'Oh, that's just a dog' or 'Oh, that's just a cattle dog that runs in my yard'."
Wayne Pacelle, president of the Humane Society of the United States, is hopeful public attitude nationwide will change.
Pacelle has a goal of greatly decreasing the overpopulation problem in the U.S. by 2015.
"It's not going to happen overnight," said Pacelle. "(But) it is going to happen. Animal by animal, person by person. And it's a tough, big national problem that we've got to confront."
Boulder is not the only area with success. Several northeastern states like New Hampshire have areas with few dogs euthanized for lack of space.
Read more on the local and national Human Societies.
Special reports in May