Leah's been busy travelling all over the country to bring you five animals that are facing big problems right here in the UK. This time she's taking a look at adders.
Snake experts are worried that though the adder is the most widespread snake in the UK, its population is getting much smaller.
It's the easiest time of year to spot the slithery things because they're just coming out of hibernation.
Leah went to try her luck at helping the experts count adders.
If you like this report, you're in luck - there's loads more from Leah coming soon!