I think you should investigate the following IOT devices which most are doggy compatible. Try the small devices that require a SIM card which has a global range whereas Bluetooth is limited to a physical maximum range of about 800 yards and usually only works within about 20 yards.
If and only if there is local coverage another alternative is to use the following:
I have been using TheThingsNetwork temperature and humidity Sensor for the past year and connect to my website with my mobile. The readings are updated every 30 minutes. I was most disappointed when I traveled around Bangkok with the Sensor in my shirt pocket and could not connect to another Gateway. Once I returned to my 19th floor apartment I was once again immediately connected.
A friend in UK, who gave me the Sensor has crowd funded nearly 50,000 USD. About 200 Contributors will receive a programmable and very small PCB that will be launched from a rocket into Low Earth Orbit, early next year. GPS and other micro devices can be fitted to the PCB all of which connect to earth bound TheThingsNetwork about 500 miles away!