Forget humans—now the king of the jungle is taking the help of Apple Watch to record his heart rate. Yes, you heard it right. Veterinarians in Australia are now using Apple Watch to monitor the heart rate of lions and other animals. This new method of wildlife health monitoring was recently shared by Australian wildlife veterinarian Dr. Chloe Buting, who posted a very fascinating video showing an Apple Watch tied to the tongue of an anesthetized lion.

This inventive method, described by Dr. Buting as an “off-label” use of Apple’s technology, certainly shows the limitless potential of technology in terms of saving lives, be they human or animal. Dr. Buting, known as @jungle_doctor on Instagram, posted this video with the caption: “The @apple Watch can measure a lion’s heart rate if you tie it to its tongue (even though this is one of the less traditional “off-label” uses for the device). Either way, this is a true ‘technology meets conservation’ story.”

Buting revealed that the technique of using the Apple Watch on animals was inspired by Dr. Fabiola Quesada, a leading wildlife and conservation veterinarian, who initially used the Apple Watch to measure the heart rate of an elephant by placing tape on its ear. This method has proven remarkably effective, given the challenges of monitoring the heart rate of large and potentially dangerous animals in the wild.

Following a similar approach, veterinarians wrapped an Apple Watch around the tongue of a lion while it was sedated so that vets could accurately monitor the animal’s heart rate. This technique ensures that the animal’s vital signs are tracked efficiently during medical procedures.

How does the Apple Watch measure heart rate

Apple Watch uses photoplethysmography technology to measure heart rate. This method is based on the principle that blood is red because it reflects red light and absorbs green light. Apple Watch uses a green LED light paired with a light-sensitive photodiode to detect the amount of blood flowing through the wrist at any given time. As the heart beats, blood flow—and the resulting absorption of green light—changes. By flashing its LED light hundreds of times per second, Apple Watch calculates heart rate by measuring these fluctuations.

According to Apple, the optical heart sensor in the Apple Watch is capable of supporting a range of 30-210 beats per minute. To increase accuracy, the sensor compensates for low signal levels by increasing both the LED brightness and the sampling rate. The sensor can also use infrared light for background heart rate measurements and notifications.

Additionally, the optical heart sensor can use infrared light for background heart rate monitoring and notifications. For activities like workouts and breathing sessions, Apple Watch uses green LED light to measure heart rate, calculate walking averages, and assess heart rate variability (HRV).

Specifically, the Apple Watch Series 4 and newer models, as well as all models of the Apple Watch Ultra, are equipped with electrodes in the Digital Crown and on the back of the watch. These can measure electrical signals in the heart when used with the Heart Rate app or the ECG app. When a finger is placed on the Digital Crown, the device picks up electrical impulses in the chest, creating a closed circuit between the heart and both arms.

For high-fidelity heart rate readings, users can open the Heart Rate app and place their finger on the Digital Crown, which takes measurements every second. The ECG app, available in some regions, can also be used to take an electrocardiogram, which provides a detailed snapshot of heart health.