LoraWAN, a wireless protocol that uses very little power and transmits small bits of data over many kilometres (depending on the conditions), is an excellent choice. This tech can be combined with a GPS receiver to create the Wildlife Asset Tracker from TRAK TFRC. The concept is simple, but implementing it properly and then verifying it is is not.
The device includes a Queltec L80 GPS module and an internal patch antenna to position it. It also has an RFM 95 board for LoRaWAN communications. Processing is done by an 8MHz, 3.3V ATmega328P microcontroller, which is programed as an Arduino Mini Pro Mini. Scheduling is made easier by implementing a real-time clock. It can switch the GPS receiver on/off with a transistor, saving power. The EEPROM can store data, protecting any information that has not been received.
This device is small enough to be used for tracking wildlife and other non-wildlife “things”. I think of automobiles, bikes, and weather balloons as possible uses, but there are many other possibilities. It doesn’t work theoretically. The device has been used to track wildlife by researchers in Peruvian Amazon. It could be a good option for tracking your wildlife!