One of the world’s most cooperative mammals is also one of its most warlike. I’m not talking about us.

The banded mongoose lives in sub-Saharan Africa. It has a long, bulky body and a pointed face, kind of like a ferret on steroids. There are many species of mongoose, but this one has dark stripes across its lower back and haunches.

The other distinctive trait of banded mongooses (not “mon-geese,” sadly) is their groups. In western Uganda, where University of Exeter evolutionary biologist Michael Cant studies them, the banded mongooses live in extended families of 10 to 20 adults, plus their children. These families are highly cooperative when it comes to raising the pups.

Among other cooperatively breeding species, such as the marmosets and tamarins, it’s common for a group to include an alpha female or couple, who do most or all of the breeding. Helpers aren’t supposed to have babies. The enforcement of this policy can be brutal: Dominant meerkat females, for instance, may forcibly evict their sisters or daughters who become pregnant.

But among the banded mongooses, any female can breed. The group’s older females do sometimes kill pups that aren’t their own. More often, though, the mongooses avoid this hazard with a neat trick they’ve evolved: They synchronize their births. In one study, 64 percent of the time, the mongooses managed it perfectly. No matter when they’d gotten pregnant, every female in the group gave birth on the same night.

No one knows exactly how they manage this, Cant tells me over a video chat, sipping a cup of tea that one of his children has just brought him. There’s likely some sort of pheromone involved. The result is that the females—suddenly surrounded by, say, five litters of newborn pups—have no idea whose kids are whose.

So the moms don’t try to keep track. Pups move from one mother to the next, nursing freely. “The females just kind of look around, and look at the sky,” Cant says, “and don’t pay any attention to who’s suckling from them at all.” All the pups have access to the same resources.

In an experiment, researchers tried to un-level the playing field by feeding cooked eggs to some pregnant mongoose mothers. Their pups were born extra big. But then the mothers of those robust pups fed more milk to the smallest pups in the litter. This made the whole group more equal again.

The cooperative care doesn’t end there. While the pups are young, a few babysitters stay behind with them each morning while the rest of the group goes out to dig up beetles and millipedes and other tasty tidbits. In the midday heat, the group returns home to nurse the babies and swap sitters for the afternoon.

Males do a lot of this babysitting, Cant says. Some mongooses are “super babysitters” who, for some reason, opt into the job much more often than anyone else, as much as six times the average.

Other mongooses seem to specialize in care for older pups, which researchers call “escorting.” An escort is an adult, most often a young adult male, who forms a one-to-one bond with a particular pup once the kids are old enough to leave the den.

Pups stay glued to the side of their escort when they’re out foraging. Escorts feed, groom, protect, and play with the pups. Young mongooses even learn habits from their escorts, such as whether they prefer to crack open hard food items by biting them or smashing them against a tree trunk. This is a kind of “cultural inheritance,” Cant tells me, like when humans pass down crafts or dance steps to the next generation.

The cooperation between the mongooses enables culture and teaching, but also incredible violence.

The danger starts at birth. Remember those babysitters at the den? They aren’t there only to protect the pups from hungry pythons or leopards. The biggest threat may be other mongooses. Cant says that if an enemy mongoose group comes across a den that’s not adequately protected, they’ll drag the pups out kicking and screaming, then decapitate them.

Who is the enemy of a mongoose? Anyone outside your own group.

When two mongoose groups run into each other, they start an all-out battle. The violence is coordinated, Cant says, and almost ritualized.

First, one individual from each group stands tall and gives what Cant calls a “battle cry.” Everyone in the group rushes together. Then they all writhe around on the ground briefly. A pungent smell fills the air. “It seems like they’re smearing each other with a uniform scent, a group scent,” Cant says.

Once the mongooses have this scented war paint on, the battle starts. It’s chaotic and vicious. The animals— mostly the males—bite and scratch and sometimes kill each other. “The reason why they’re so deadly is because they work together as a group,” Cant says. In slow-motion video, the mongooses seem to use rapid-fire sniffing to distinguish who’s on their team and who’s the enemy.

There’s another way in which these battles are more than meets the eye.

Years ago, the team of Ugandan field researchers who watch the mongooses daily — and who can identify every mongoose by sight, Cant says, unlike him or his colleagues in the U.K. — shared something that sounded outlandish. They believed that these violent scenes between mongoose groups were no accident. Rather, the battles were orchestrated by the females.

Cant put together a formal study and found that his team was right.

The cooperation between the mongooses enables culture and teaching, but also incredible violence.

Female mongooses occasionally need to mate with someone outside their group. As it is, “incest is quite common,” Cant says. Letting the pups get too inbred would harm the group’s health. But when females are fertile, males in their group guard them from outsiders by following them nonstop, nose-to-tail.

What’s a woman to do? She starts a war.

A fertile female sometimes walks right into enemy territory, trailing her nosy guard behind. When the males from the two groups bump into each other, a fight starts. The battle cry is sounded; the mongooses face off shoulder to shoulder. Then the mayhem begins. While the males are fighting, the female sneaks off to get some quick action behind enemy lines.

This all sounds like something out of an ancient Greek epic. It strikes me, I tell Cant, that mongooses and humans have separately evolved to be alike in two ways: our highly cooperative communities, and our proclivity for warfare.

“I’m quite cautious about drawing too many direct parallels,” Cant says. But he does wonder whether studying other species that go to war could help us understand that side of ourselves. Just as we’ve learned about the evolution of cooperation from animals ranging from wasps to whales.

No matter why the mongooses evolved this way, Cant knows that the ever-present threat of battle makes it even more vital to stick with your team.

“The warfare is so intense,” he says. “If you don’t have a large, strong group, you’re going to get wiped out.” Staying alive means staying together.