Kruger Park testing solar-powered eartags to track wildlife

The Kruger National Park has started testing GPS ear tags powered by mini solar panels to track the locations of wildlife.

Several visitors to the park have spotted these trackers pierced onto the ears of various animals — including kudu, waterbuck, and rhino — over the past few weeks.

One of the visitors was James Cary, who took the image of the kudu above on the S36 in central Kruger.

Tracking wildlife is important for scientific research, which could help humans better understand animal behaviour and devise ways of ensuring their continued survival, particularly in confined areas like national parks.

Newer, more advanced tracking technologies can also help proactively safeguard species vulnerable to poaching or other immediate threats.

For many years, SANParks and third-party wildlife researchers have used bulky GPS-fitted collars to monitor animals’ locations.

These collars have several glaring shortcomings and are not suited for use on all animals.

Because they need to track the locations of animals, they are fitted with GPS, which consumes a lot of power.

Some collars store data on the collar itself, which can only be downloaded after the animal is tranquilised and captured.

To help with locating the animal, the collar emits a VHF radio signal. Finding the collar is nonetheless a big challenge with animals like leopards, who have large roaming territories.

Other collars can transmit their location to a satellite every few hours — typically on the Iridium network — which, in turn, transmits the data to a server on the ground. This allows for remote tracking capability but is more power-intensive.

The battery packs in these collars can last several years but are large and cumbersome, meaning they are generally only suited to larger, adult animals.

The irregular shape of the rhino’s neck and shoulders also make collars unsuitable for tracking them — a major target for poachers.

Fortunately, in the past few years, substantial technological advancements have opened up new possibilities for more compact and useful devices.

Modern smart trackers like Apple AirTags, Galaxy SmartTags, or Tile trackers use Bluetooth and Ultra-Wide Band communication to transmit their locations, rather than GPS.

That ensures their batteries can last for multiple months to several years.

However, these can only be effective in areas where there are many other Bluetooth-enabled devices, which can help ping the locations of the trackers for other users.

There are also compact and specialised GPS-fitted collars for keeping track of pets, but their smaller battery packs require charging every few days.

Solar power comes to the rescue

By using small solar panels, innovative companies have created compact new trackers that don’t require large batteries without sacrificing the ability to transmit locations and other important data remotely.

Although SANParks has confirmed it is trialling these types of tracking tags, it could not immediately provide more details, as its teams with first-hand information on the project were out in the field at the time of our queries.

Two companies that offer compact solar-powered trackers for animals and other assets in South Africa are Ceres and GSatSolar.

These trackers were originally made to monitor livestock and other moveable assets.

Ceres offers three small solar-powered trackers — Ceres Ranch, Ceres Trace, and Ceres Wild.

The Ranch has built-in direct-to-satellite capability, with up to four location updates per day, and is priced from $166 per tag in the largest bulk box.

The Trace boasts support for newer low-earth orbit satellite networks, with the same number of daily pings and the same starting price.

For reference, GPS-fitted collars typically send their location around eight times over 24 hours — or about every three hours — using the Iridium satellite network.

However, the top-end $660 Ceres Wild also has direct-to-satellite capability and can transmit up to 24 location pings per day.

According to GSat, its $199 tracker can provide up to 12 location pings to the Iridium satellite network with a day’s worth of solar charging of its 150Ah battery.

That is despite its small solar panel array generating a maximum of 0.125 watts of power.

Using multiple trackers

One additional benefit of solar trackers’ smaller form factors and weights is that more can be fitted to an animal without causing strain.

For example, the Ceres Wild weighs just 35g and measures 62mm long, 36mm wide, and 37mm thick.

In addition to locations, it also comes with advanced activity metrics to track unusual behaviour, mortality, and geofence boundary crossings.

The GSatSolar weighs around 31g, including its additional components for attaching to an animal’s ear.

By fitting an animal with a tracker on each ear, researchers and wildlife protection agents can effectively get double the number of location pings without additional battery losses.

It also provides redundancy if one of the trackers is damaged, lost, or destroyed.