But to get to the nuts, they must leap between the colored discs.
The blue discs stand firm; the red discs are wobbly.
The idea is that they'll learn the difference and just use the stable blues to get across.
But it's proving to be a very difficult challenge.
'The squirrels will get to the start, quite literally just have a look at it and think, 'Nah, not a chance,' and just completely give up before they even give it a go.
Others have given it a go but fallen off halfway which is what I was expecting.
It's a very tough obstacle.'
Part of the learning process is testing things out and making mistakes.
But with their favorite nuts in plain sight, the squirrels are utterly determined.
So quick, oh my gosh.'
And finally, they find their own way of getting across.
'The squirrels have figured out an incredible solution.
They take one step on the reds and two steps to steady themselves on the blue.
So they go one, one-two, one, one-two, one, one-two.
Using speed and agility to overcome the cognitive problem.'
Driven on by their desire for nuts, they've combined their grip, persistence, memory and problem-solving skills, and earned their prize of a nice, big hazelnut!