Reputation: It's so cute the way meerkats stand on their hind legs. They live in large, caring, harmonious groups. They love eating scorpions. They are always fighting cobras.

Reality: Meerkats spend most of their time on all fours. They do eat scorpions, but not as often as TV makes out. Group-living isn't always as congenial as it would seem. Meerkats have a dark side and females will sometimes end up killing babies. Confrontations with cobras are rare.

Twenty years ago, I spent nine months walking with meerkats in the Kalahari Desert. I was one of the first graduate volunteers on the long-running Kalahari Meerkat Project. I remember having to pull a stuffed caracal – a sleek, lynx-like cat – towards different groups of meerkats, with the aim of figuring out how they perceive and communicate different levels of threat.

It's at this time of day that they look most like little people

Meerkat groups range from 3 to 50 individuals. They usually comprise a dominant pair; a few other non-breeding adults; a rabble of juveniles, often from several reproductive events; and a cluster of impossibly cute pups. At dawn, a group will emerge from its overnight den and before heading off for the day's foraging, the meerkats must take several minutes to warm up on the top of their burrow.

The vertical posture they adopt – sometimes resting on their haunches, sometimes standing, with their tail acting like the third leg of a tripod – offers the greatest surface area to the rising sun. It also makes for terrific photos: the lighting is great and the animals don't move much.

But the real reason that we see so many images of sunning meerkats is their anthropogenic posture. It's at this time of day that they look most like little people.

For most of their waking lives, however, meerkats are on all fours in search of food.

"Meerkats are always digging," says Marta Manser of the University of Zurich in Switzerland. She has worked on the Kalahari Meerkat Project for more than 20 years and was the researcher I helped with the caracal experiment in the 1990s. "None of the other mongoose species invests as much time in digging."

A foraging meerkat will occasionally come across the entrance to a scorpion burrow and have a go at digging it out, but scorpions are not the staple that most TV documentaries would have us believe. In a thorough study of meerkat diet and foraging behaviour in the 1980s, some 80% of all food items were tiny insects – mostly beetle larvae and adults – whilst only 2% were scorpions.

When they are foraging, one of the meerkats – often the dominant male or female – will forego food for extended periods. It climbs to a position of prominence, which can be a researcher's head, to keep a lookout for predators.

Meerkats don't appear to have actual "words" for specific predators

Over the years, Manser's research – recording meerkat calls, studying their acoustic structure, and observing the reaction to carefully-controlled playbacks – has revealed how a meerkat tells the rest of the group about approaching danger.

There are two main categories of call: one for ground-based threats like a caracal or black-backed jackal, and another for aerial threats like eagles. Although meerkats don't appear to have actual "words" for specific predators, they do inject their alarm calls with a level of urgency.

"If you combine these streams of information, it could in theory be enough to communicate the exact species in question," says Manser. It would take a human several words to convey the presence of a martial eagle at a distance of 500m. It has not yet been demonstrated experimentally, but a meerkat may be able to transmit all this information in a single, urgent bark, she says.

In 2012, Manser hit upon a brilliantly simple experiment to test whether meerkat calls communicate the identity of the caller. Having identified a meerkat for the experiment, she and her colleagues simultaneously played it calls recorded from one individual but from two different places. "They notice the contradiction," says Manser.

A study the following year demonstrated that this kind of individual recognition is particularly relevant when it comes to the balance of power between females. For instance, when the dominant female is pregnant, playbacks of her call are quick to trigger submissive behaviour amongst subordinate females. If the dominant female is not pregnant, or the call comes from any other individual, the subordinates simply aren't bothered.

This touches on another truth about meerkats, one that sits a little uncomfortably with the caring, sharing stereotype. When the reproductive hierarchy is clear, meerkat society is amiable enough. But when the hierarchy breaks down, says Manser, "meerkats aren't quite so cute."

In particular, woe betide any subordinate female that has the temerity to fall pregnant and give birth. Her offspring will often be killed.

In every one of these episodes, the offender ended the life of a close relative

The first publication to describe infanticide in meerkats in detail, published in 1998, reported on six cases that had been observed directly in the course of five years. Warning: the following excerpt from the research paper reveals a dark side to meerkats that some readers – particularly those wedded to the cutesey cliche – may find distressing.

"In all these cases, female group members carried pups out of a breeding burrow where they had been born less than 24 h earlier and killed and/or ate them in the presence of an observer."

In every one of these episodes, the murderous and/or cannibalistic offender ended the life of a close relative: a nephew, niece, sibling, cousin and, on one occasion, a daughter.

In addition, there were several instances where pups were dispatched by rampaging meerkats from a neighbouring group.

This infanticidal behaviour might be crucial for maintaining the stability of the group

More disturbingly still, the researchers concluded there is probably a whole lot more infanticide that goes undetected below ground. It would be the obvious explanation for the fact that the pups of a subordinate are far less likely to emerge from the birthing den than those of a dominant.

As brutal as this infanticidal behaviour might be, it's probably crucial for maintaining the stability of the group, and hence boosting each meerkat's chances of survival.

And what about those feisty confrontations between meerkats and cape cobras? "I have probably seen it about 3 times in 20 years," says Manser. But it's a whole lot more common when there's a documentary to be made. "The film teams bring in a person with a snake," she says.

Tweetable truths about meerkats

Tweet: A meerkat can probably say "There's a martial eagle incoming at 500m!" in a single, urgent bark

Tweet: When a meerkat is foraging, only 1 in 50 food items is a scorpion

Tweet: Meerkats can tell the identity of other individuals from their calls