To end the week, let’s have a feel-good video of a group of Emperor Penguin chicks, threatened by a hungry petrel, get saved not only by their own defensive behavior, but also by the timely intervention of an Adélie Penguin. Among the smallest of penguins, Adélies are nevertheless fierce. (I’m also impressed by the huddling of the Emperor chicks and the one who holds up its flippers to protect the others.)
Now, you may ask yourself, why would an Adélie trouble itself to save members of another species? It’s only taking a risk with no possible benefit to its genes. There are some answers, but I’ll let you think of them. Put them below in the comments.
From the BBC:
I used to show this clip when I taught Evolution and ask the students for an explanation of the Adelie’s behavior.
Sub
I think it’s just instinct. Adelie hears chicks in trouble, sees its arch-enemy – the petrel – and responds instinctively. It doesn’t “know” that it’s not related to the chicks. It’s just doing what comes naturally when it sees chicks and predators.
I think this is correct. Dogs have the same instinct. Not all dogs, of course, and I wouldn’t be surprised if this Adelie behavior is rare.
That’s also my take. Petrels = danger to the Adelie, and it may have evolved (or learned?) simply to drive them away.
That begs the question of whether Adélie penguins can, cannot, or don’t care, about the identity of a chick. Since other penguins certainly show parent-chick fidelity, I think the only one of those options that stands scrutiny is “don’t care”.
The downsides of this ignoring of chick identity are risk of injury to the adult penguin, but with a good side serving of “starving the chicks of my fellow-penguin’s enemy is starving the chicks of my enemy”. Which is not a great disincentive.
Yes, that is indeed the most plausible hypothesis.
The lunch target of my enemy is my friend.
Maybe Adélie penguin is less likely to miss protecting an Adelie chick if he has a broad definition of what chicks must be protected. Hence a benefit to its genes.
Maybe the Adelie has been subjected to current academic fashions, and thinks that species are on a spectrum (at least in Penguin world). Come to think of it, do we know for sure that
Adelies and Emperors are entirely isolated reproductively? Perhaps there are hybrid Emperdelies lurking in Antartica, just as there are rumored to be biPolar Bears.
Impressive.
Reciprocity. Tit for tat (Axelrod et al) shown to be the best way statistically for animals to survive. Vampire bats sharing the contents of their blood sacs with those who returned empty after a night’s hunting. etc. See Robert Sapolsky ‘Behave’ and ‘Determined’ – both wonderful and mind-opening reads.