1This is a poison dart frog.
2Males raise their young in a very special way.
3A father will place each one of his tadpoles in its own tiny pool of water.
4This is one. Nice and safe.
5He might have up to five other tadpoles...
6but he needs to remember where he put each one of them.
7This one isn't doing so well.
8His tiny puddle has all but dried out.
9The tadpole will die unless its father can find a better place for it.
10If dads are good for one thing, it's piggyback rides.
11...
12Fathers are no bigger than a human thumbnail,
13but this enables them to get to places that others can't.
14This could be perfect.
15The only problem is that there's no food here.
16Fathers need help.
17Somewhere in this forest...
18is... Mum.
19A female could do something a male cannot.
20But first, Dad must lead his partner to their hungry tadpole.
21...
22And Mother deals with the problem.
23She lays a single unfertilised egg.
24And her tadpole gets a much-needed meal.
25For the next six weeks, parents continue their rounds.
26An extraordinary test of teamwork and memory.