We live in the age of tracking. Americans of all shapes and sizes strap gadgets to their wrists to track activity levels, sleep patterns and moods. We use apps on our phones to track our locations (and that of our loved ones) and we set up gadgets in our homes to track security and energy use while we're away. So it seems like a natural next step that we might want to add GPS to our pet's collar. But do you really need a GPS tracker for your pet?

That all depends on what you hope to achieve. Pet GPS and activity tracker systems come in a wide variety of options and price ranges. Unlike microchips — which do not contain GPS systems and must be scanned by a microchip reader to provide any useful information — pet trackers can be used to pinpoint the location of a lost pet and/or keep track of his daily activity. They are typically found in tags that attach snugly to your pet's collar.

Here are some options to consider.

If you want to track your pet's health

Heard of Fitbit? Meet the FitBark. This activity tracker is a great tool for the data-obsessed who want to know not only when their dog is resting or playing but also how fit the dog is compared to other dogs of the same age. (Are they average or Olympian?) There's also a social aspect to the FitBark that lets you share tracking info with others (your vet, your kids, your dog walker) and even find out which other pets she is hanging out with during the day. Oh, and you can link your own fitness tracker to your pet's FitBark if you feel the need to compare your fitness to hers.

If you just want to know where your pet is

What if you just want to be able to locate your pet if he gets lost? There are a number of dog GPS trackers that can help you with that. Marco Polo, PodTracker, Tractive GPS tracker and Gibi are just a few of the models that offer peace of mind for anyone whose pet likes to dig under the fence or bolt through the back door.

PodTracker, Tractive and Gibi are all subscription-based services, so you'll need to shell out an additional monthly or yearly service fee to keep track of your pet. The advantage is that they can accurately pinpoint your pet's location in a jiffy if he gets lost. Tractive even comes with a light and beeper that you can activate to make it easier to find Fido in the dark.

If you want to keep track of your pet without the subscription commitment, you might want to try Marco Polo. This tracker uses a hand-held portable locator that syncs with a collar and tag. So you wouldn't need to turn it on unless your pet was actually lost. It's great for those with spotty Internet coverage or cell service, but the disadvantage is that the unit only has a range of two miles, so if your pet tends to wander further, this might not help you out.

If you want it all

Want to track your pet's location and her health? Try the Whistle. With the Whistle dog tracker, you can instantly track your pet's location, monitor her activity level and health, and even keep track of her medications. You can also set daily health goals and keep track of changes in activity level and sleep.

One caveat about all of the data collected by an activity tracker for your pet is that you may have to watch that data peak — and then decline. Blogger Molly McHugh describes in poignant detail in this piece on Wired what it's like to see an aging dog become less active via charts and daily notifications.

"I can see the decline — which is such a strange thing to see defined in an app. Usually, these sorts of services are about living better...[b]ut what about when a tracker isn’t showing that you’re getting better — what if it says you’re getting worse? If someone were to wear one of these things forever, they’d notice a change from improving their body to watching it die."

Is that something you really want to see? In this tracking-obsessed age, this is a question we might all have to ask, about ourselves — and our pets.