Why Do Meerkats Stand Up? Sentinels, Alarm Calls and Sunbathing

Standing up to watch for danger

The meerkat is a small mongoose, weighing well under 1 kg (2.2 lb), that lives in the dry, open grassland and scrub of southern Africa. Almost everything out there wants to eat it. Martial eagles, tawny eagles, pale chanting goshawks and lanner falcons hunt from the air, while black-backed jackals, Cape foxes, honey badgers and Cape cobras threaten meerkats on the ground, especially the pups.

A meerkat’s eyes are only a few centimeters above the ground when it walks on all fours, and short grass and shrubs block its view. By rearing up on its hind legs, it lifts its head several times higher and can scan a much wider area. Its large, forward-facing eyes give good binocular vision, and the dark patches around them are thought to reduce glare from the bright desert light, which helps when searching the sky for a distant raptor.

The tail plays an important part. A standing meerkat balances on its hind feet and leans on its stiff tail like the third leg of a tripod, which lets it stay upright and almost motionless for long stretches.

What is a meerkat sentinel?

Meerkats spend five to eight hours a day foraging, and most of that time their heads are down, digging for beetle larvae, scorpions and other prey (see What do meerkats eat?). A digging meerkat cannot watch for danger at the same time. The solution is the sentinel, or guard.

While the mob forages, one adult (sometimes two) climbs onto a raised lookout such as a termite mound, a rock, a fallen log or a low branch in a bush or tree, stands up and keeps watch. Sentinels often choose the highest point nearby, sometimes climbing a meter or more off the ground. When one sentinel comes down, another meerkat often takes its place, so on many days the group has a lookout for much of the time it is foraging.

Sentinel duty is not a fixed job. Any adult or older juvenile can do it, and members of a mob take turns in a loose, informal way rather than following a rota.

The watchman’s song and alarm calls

A sentinel is not silent. While on guard it gives a soft, regular call that researchers have nicknamed the “watchman’s song.” This steady signal tells the foragers that someone is on lookout and all is well. Studies of wild meerkats found that foragers spend less time looking up and more time feeding when they can hear a sentinel calling, so the whole mob eats more efficiently.

When a sentinel spots a threat, it switches to an alarm call. Work by Marta Manser, published in 2001, showed that meerkat alarm calls differ by the type of predator and by how urgent the danger is:

High-urgency calls, given when a predator is close, trigger faster and stronger reactions than low-urgency calls about a distant threat. This makes meerkat alarm calls one of the best-studied examples of animals passing on information about both what the danger is and how serious it is.

Is being a sentinel dangerous?

It might seem that the sentinel risks its life for the group, standing exposed on a high perch. Research says otherwise. In a 1999 study in Science, Tim Clutton-Brock and colleagues at the Kalahari Meerkat Project found that meerkats usually go on guard after they have eaten their fill, and that individuals given extra food took more turns on sentinel duty.

The same study found no evidence that sentinels were killed more often than foragers. A sentinel is the first to see danger and is usually close to a bolt-hole, so it is often among the first to reach safety. Standing guard seems to be a sensible choice for a well-fed meerkat that has little to gain from more foraging, and the mob benefits at the same time. The researchers described this as “selfish” vigilance that still helps everyone.

Standing up to sunbathe

Not every upright meerkat is on guard. Desert nights in the Kalahari can drop below freezing in winter, and meerkats have a low metabolic rate for a mammal of their size, which saves food and water but means they produce little body heat.

Each morning, the mob emerges from the burrow and sits or stands in the sun, often facing it with the belly exposed. The fur on a meerkat’s belly is sparse and the skin underneath is dark, so this patch works like a small solar panel that absorbs warmth. Only once they are warmed up do meerkats head off to forage. In the heat of the day, by contrast, they rest in shade or underground.

Other reasons meerkats rear up

Meerkats also stand briefly on their hind legs in other situations:

• Checking an alarm. After hearing a call, meerkats near the burrow often pop up to look for themselves before deciding whether to bolt.
• Watching rivals. Neighboring mobs defend territories, and meerkats rise up to watch another group approach. These encounters can turn violent.
• Looking out from burrow entrances. After danger passes, meerkats peer out of the hole, then stand up at the entrance to make sure the coast is clear.

Do other animals stand up like meerkats?

Several burrowing animals of open country share the habit, which shows how useful it is when predators can come from any direction. Prairie dogs in North America and ground squirrels in many parts of the world rear up at their burrows and give alarm calls, and the groundhog often stands upright to look around near its den. In southern Africa, Cape ground squirrels sometimes share burrows with meerkats.

These animals are rodents, while meerkats are mongooses in the order Carnivora, so the similarity evolved independently. The difference is explained in Is a meerkat a rodent?.