"Bark! Bark-bark! Bark!" What is it, Lassie? What are you trying to say?

No, Timmy hasn't fallen into the well. Lassie, Fido, Rover and Spot are all trying to tell their humans that it's time to get the leashes out for the 37th Annual K-9 Fun Run and Walk.

At 37 years Houston's oldest dog walk isn't celebrating a big milestone like a 35th or 40th anniversary. But it's a good indicator that the Houston Humane Society's mission — to work toward ending cruelty, abuse and the overpopulation of animals — is a worthwhile cause.

"We’ve been fortunate at the Houston Humane Society to have the community support in a number of ways, including at the annual fun run. It’s a fun event for the community. Come out, learn about the [society] but also support the nearly 50,000 animals a year that the agency helps," says Monica Schmidt, the shelter's operations manager.

The nonprofit is not affiliated with a national organization and only serves local animals. "Primarily we’re known for helping dogs and cats but our organization also helps horses, donkeys, livestock. Mini mammals like rabbits, guinea pigs, hamsters, bird, reptiles. We’ve even had a fish come in the door," says Schmidt. "We help animals in Harris, Fort Bend, Brazoria, Galveston and Montgomery County. Really, our immediate area."

The race entry fee gets a limited edition racing shirt for the human and a bandana for the canine, plus a goody bag. Schmidt says the shirt was designed by Louisiana artist Jim Tweedy who also shows here in Houston.

Tweedy is famous for his friendly dog designs, including last year's Houston Arphabet (with acrobatic dogs forming the letters) where a portion of sales were directed to animal rescue efforts in the aftermath of Hurricane Harvey.

Schmidt says they keep the course to one mile so the dogs don't get stressed out or tired. "We have five percent do the competitive run and 95 percent do a leisurely stroll. It's more of a laid back event." Which is good, because smart pups know to save their energy for the after party.

"We have a post race party with live music and a doggy costume contest," says Schmidt. There's also an alumni parade where previous adopters can go over a ramp, introduce their dog, and say when he or she was adopted. "There's a gift for the oldest alumni and it allows people to see the animals they're supporting."

This is their second year at Lynn Eusan Park on the grounds of University of Houston. "We've got pet friendly vendors, refreshments. It's a big old party in the park. We usually have close to 500 people," says Schmidt.

Dogs are optional for participating, though. Cat owners can leave Fluffy at home but still come out to support the society, and there's even an option for those who want to sleep in but still contribute.

Race entry fees and donations help the society perform about 10,000 low cost spay and neuter surgeries each year, operate an animal crime unit, offer low cost vaccinations and maintain a wellness clinic that's open seven days a week.

The 37th Annual K-9 Fun Run and Walk runs from 8 a.m. to noon April 22, Lynn Eusan Park, University of Houston, 4800 Calhoun, 713-433-6421, houstonhumane.org, $25 to $40.