The drains team used an endoscopic camera in the tunnels
Drains specialists have been brought in to a Devon zoo to find out what meerkats are getting up to in their network of underground passages.
The meerkats have 40ft (12m) of tunnels in their new enclosure at Dartmoor Zoological Park.
But the zoo wants to ensure they do not breed below ground because it wants to monitor them properly in a nesting box if they have any offspring.
The drains team used an endoscopic camera in the tunnels to monitor them.
The network of man-made tunnels under the enclosure which is home to meerkats Sue and Timon are to replicate their natural environment.
But keepers think Sue is pregnant, or will be soon, and they want to keep an eye on her.
The park's Colin Northcott said: "If they're going to breed we want the right conditions for them and, if they're going to breed inside the tunnel, we basically need to know what's going on."
The first sweep of the tunnels found that they were not nesting below because it was too wet after a tunnel flooded.
The drains workers said the task they were given was "very different".
Lee Hubber, from Lanes for Drains, said: "At first we thought our managers were having a laugh with us but it's just part of the job really.
"This would usually be used for looking for defective lines in sewage lines, that sort of thing, not usually looking for meerkats."
The zoo is to use the pictures from the work to prevent water from getting into the tunnels again.