You can use wearables with GPS to keep track of wandering dogs. Others help you track animals' physical activity.

Now, two companies have the latest in wearable pet technology: collars that can check for a fever, monitor pulse and respiration, and even indicate if your pet is in pain.

PetPace, based in Burlington, Massachusetts, has a medical collar that can measure a dog's vital signs and other information to look for signs of pain.

Irregularities trigger a notice by phone, text or email.

Voyce, created by I4C Innovations Inc., and based in Chantilly, Virginia, has a consumer version that tracks similar information.

It also has a Voyce Pro that is available to veterinarians to prescribe for pets recovering from surgery or long-term illness.

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Both smart collars can be programmed to monitor for a pet's specific illness. Dogs and cats over 8 pounds can use them.

Kenneth Herring, who lives outside Detroit, uses PetPace to monitor his 5-year-old dog, Jack, as part of a test case to see how effective the collar is in helping detect epilepsy.

When Jack has a seizure, he keels over on his side, drools and may lose consciousness, Herring said. So far, his twitching limbs and lack of motion have been enough to trigger an alert, and PetPace plans to use what they learn from Jack to tailor the collar to other dogs with epilepsy.

Michelle Saltzman, of Bedford, Massachusetts, uses PetPace for Lucas, a 10-year-old beagle she adopted in October. Lucas has a heart murmur and suffers from fainting spells, and the monitor allows Saltzman to leave the dog home alone without worrying.

PetPace's medical monitoring collar came out three years ago and has been tested on thousands of dogs.

Voyce for pet owners was introduced in the spring, followed by a professional version for veterinarians in July. More than 100 animal hospitals have signed on to use Voyce Pro, said Emily Hartman, director of product management for I4C Innovations.

PetPace collars are available at petpace.com for $150 per collar and $15 a month, while Voyce is available at voyce.com for $200 and $9.95 a month.

Herring said the smart collars do have limitations, including batteries that last anywhere from two days to eight weeks, depending on how much data they are asked to measure and deliver.

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Some of Jack's vitals are checked every two minutes and some are checked every 15 minutes, so the batteries drain in two days and it takes two hours to recharge - time when Jack does not have the collar on, Herring said.

One of the reasons PetPace did not put GPS on its smart collar was to save on battery power, said Dr. Asaf Dagan, PetPace's chief veterinary scientist and co-founder.