(CNN) -- — What is your dog doing right now? Is he taking a nap? Furiously digging a hole in your garden? Watching "Ellen" and nibbling on a throw pillow?
For people with jobs away from home, eight hours can seem like a long time to be separated from a beloved pet. Now, a new crop of wearable trackers can give curious or concerned owners real-time information about what their dog is doing.
That data can then be collected over time to learn more about a pet's habits and even spot early signs of health troubles that humans might miss.
San Francisco company Whistle launched its first product on Wednesday: a $100 wearable activity tracker that attaches to a dog's collar.
The trackers are small, brushed-metallic discs, just light enough for any dog over seven pounds to ignore while he goes about usual daytime activities, blissfully unaware he's living in a surveillance state.
"We would love to be able to help these dogs live longer lives," said Whistle co-founder and CEO Ben Jacobs. "The No. 1 indicator of a dog's health is its own activity compared to its base line."
The tracker uses an accelerometer to determine if a dog is resting, playing or sleeping. That data is synced using Wi-Fi or Bluetooth, and the owner can see it all on a smartphone app.
It's not always obvious when a pet is sick, and the first signs might be subtle changes in energy or behavior. The app will monitor for changes and also make light suggestions, such as saying it's time for a walk.
"We'll give playful hints, but we never want to judge a pet parent, just like you never want to judge a child's parent," Jacobs said.
If they take off, pet trackers might be able make a dent in the problem of pet obesity. More than half of dogs and cats in the United States reportedly are overweight.
The data isn't just for the owners. The Whistle app has a view that shows patterns over time that vets can use to help diagnose dogs. The data is also anonymized (dogs need their privacy, too) and collected in an aggregate database shared with veterinary researchers at institutions such as the University of Pennsylvania.
Whistle already has 20 employees and has raised $6 million in funding from Silicon Valley venture capital firms for its pet tech.
That number might seem shocking until you consider that pets are big money in the United States, where there are slightly more dogs than children. People reportedly spent more than $50 billion on their pets in 2012, including purchasing animals, feeding them, and paying for veterinary care and pet accessories.
An estimated $370 million was spent just on Halloween costumes for pets.
Silicon Valley and entrepreneurs have taken notice and are churning out dog and cat products, many playing off existing successful startups for humans.
On Kickstarter, a company called FitBark is raising money for a similar product that will monitor activity levels, though it appears less ambitious with its data, storing it for three weeks. Its take on the FitBit for dogs will be in the shape of a bone and also cost about $100.
Dogtek makes Eyenimal, a GoPro-esque wearable camera for cats and dogs that record their adventures, and GPS collars such as SpotLight can act as a "Find my iPhone" for lost dogs.
BarkBox is a monthly subscription service in the spirit of BirchBox that delivers a package of dog-related items such as treats and toys for $19 to $29 a month.
And, of course, there is an Airbnb for pets. DogVaycay connects dog owners with local dog sitters as an alternative to leaving pets in a kennel when they travel.
The numbers suggest people who love their pets and think of them as members of the family won't hesitate to spend money on the next wave of pet-friendly tech, especially if it can help keep their best friends healthy and happy.