In the wild, it doesn’t often pay to be nice.

Survival is of utmost importance, and wild animals have to look out for themselves and their young first.

But they’re not always the most emotionally sensitive.

When female jackdaws are in distress, their male partners can sense it. But they often don’t console their partners and focus on protecting themselves instead.

Researchers documented this behavior in a study published Tuesday in Royal Society Open Science.

So, the male’s aloof behavior might be a survival tool, despite how insensitive it looks to us humans.

Males eager to breed will sometimes kill babies that aren’t their own.

But here’s something that may come as a surprise: they’re brood parasites.

Other birds, like cuckoos, also practice this type of parasitism.

And when males are old enough to fend for themselves, they’re kicked out of the pack and left to become nomads.

In this cat-eat-cat world, only the strongest survive.

But they’re known to prioritize the healthier baby, while leaving the other to perish.

While it might seem brutal, this practice isn’t uncommon among wild animals.

This behavior fits into what Darwin first named the sexual selection hypothesis:

Animals will do anything to make sure their genes are passed on, instead of another’s.