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[DeAnglis] I use anemone fishes as a model for parental care because
they are such a good model and understanding fatherhood and fathering behavior.
Anemone fish... so anemone fish are known... that's 'Nemo.'
Anemone fish, amphiprion oscellaris...
People know them as clownfish or anemone fish.
I have to call them an anemone fish... should I call clownfish?
I love them because they're, I think they're just beautiful fish.
And they are so different from other species in so many ways.
They are found in the Indo-Pacific ocean. And they are extremely tied to their sea anemone.
So they have this host...
[DeAngelis] which is basically a jellyfish, upside down, stuck to a rock.
So it stings everything. It stings other fish and eats other fish.
[Rhodes] But the anemone fish can live in the tentacles of the anemone.
And so they're protected from predators in this way.
I went and saw them in Indonesia.
And you don't see them any more than a foot away from their sea anemone.
And as soon as they feel scared, they'll dive right in there.
And so they're isolated to that one anemone.
[DeAngelis] So they have a small home-range.
They have these really, sort of, simple social groups.
They are monogamous.
They form these lifelong, monogamous pair bonds.
[Rhodes] It also just fascinates me that there's this switch,
where the females are always the larger of the pair.
And they are the boss.
So they are the dominant individual.
And the male does a majority of the care of the offspring.
[DeAngelis] Males are not swimming all over, fighting with other males.
They're just on their anemone, taking care of the eggs...
nipping the eggs, keeping them free of fungus and debris...
and then fanning eggs, providing oxygen-rich water.
[So that's nipping.]
[That's fanning.]
And so it allows us to really look at how that egg-caring behavior is facilitated by the brain,
in a way that that behavior can be isolated.
[Rhodes] Basically what we're studying is the chemistry of a brain
and how it needs to change in order to produce these big shifts and behavior;
from thinking about yourself, to caring for your offspring.
[DeAngelis] So, what we did was, we take individuals that are fathering and we give them an injection.
And we analyze how these antagonists, or how these drugs,
either promote or inhibit male parental effort.
[Rhodes] One of the big chemicals that plays a key role in transitioning an animal from
taking care themselves, to taking care of their offspring, is this peptide called oxytocin.
[DeAngelis] Oxytocin is a well-known neural hormone that promotes
milk production and maternal bonding with the infant.
[Rhodes] So oxytocin is clearly involved in mothering in other species.
What we didn't really know is whether oxycontin is also involved in fathering.
And we found that, if you block oxytocin signaling during
parental care in the anemone fish,
you dramatically reduce the amount of parental effort...
so number of nips and fans, and time in the nest.
These males are exhibiting somewhere around 400 parental behavioral acts,
per 10-minute observation period.
And that goes down to something like 50.
[Rhodes] That was one of our discoveries.
That, yes, in fact, when you prevent oxytocin from acting the way
it's supposed to, by introducing a drug that prevents it from binding to receptors,
the male's don't parent as much. They don't fan as much.
They don't nip the eggs as much. They're doing other things.
They're being more selfish.
So that was one of the discoveries.
The other discovery, of course, was a related molecule to oxytocin, that we didn't know as much about.
It's called arginine vasopressin in mammals.
And we know that it's involved in aggression, and social interactions, and so forth.
But, in a lot of species, it has had many different roles.
[DeAngelis] Surprisingly, if you block arginine vasopressin, you actually increase male parental effort.
So they're nipping and fanning even more than they already originally do.
So we think that, by blocking vasopressin, we reduce aggression and reduce vigilance.
And, by doing so, we allow more effort to be directed towards parental care.
So this paper shows you... first, that no matter what species you are, or what sex you are,
if you're the parenting sex, generally it seems that oxytocin is a good thing for high levels of parental care.
The second thing is that, if you block vasotocin, you increase the parental effort.
To me, that's the more exciting result.
Because it's so strange that you would increase, specifically, parental effort and not other behaviors.
This is just the tip of the iceberg.
In some ways, I think, what next is even more exciting than that.
Where do we go from here? What does that really mean?
How do we test this? How do we prove this?
Those are things we're working on now.
[Rhodes] Is this something that could explain why certain individuals a better fathers?
Why certain species have better paternal care than others?
It's a very complicated process, obviously.
And it's going to involve many other chemicals.
So it's really trying to understand the full picture.
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