It’s easy to think that humans are the only species that have true friendships, but animals make friends too. And what do we know about these friendships? Well, we thought for long time that animals only have friends for biological reasons, so their genes will continue. After all, it’s easier for animals to survive with the help of another animal. We thought that animals only helped each other to get help in return. But there is growing evidence that tells us this isn’t true. Animals can also be generous, and give up something important for a friend, without expecting anything back from them, just like humans. And what about friendships between animals from different species? Like the bird that looked after the cat you mean? Those friendships are very interesting. We actually know very little about them at the moment. But we’re starting to look at them more closely.