A GROUP of penguins left traumatised by a gang of yobs have had to go on medication in an effort to calm them down.

The birds were left so stressed-out by the three rampaging thugs that they have been put on special drugs to help them sleep and relax.

The ten birds at Scarborough’s Sea Life Centre were distraught after the gang broke into their enclosure and chased them around in a bizarre effort to catch them.

And now, nearly three weeks later, they are still being administered with relaxing herbal drugs twice a day.

“Since the break-in their whole behaviour and the dynamics of the group has changed,” said displays curator Lyndsey Crawford, 33.

“They are on guard all the time, half of them aren't sleeping because they are on watch.

“They are very nervous and they stay in the water. If they are out of the water they run around all frantic.”

She said the pills they were giving the birds - along with their usual herrings - calmed them down and helped them to breathe.

She added: “Birds are renowned for having extremely high stress levels and stress can actually kill them.”

Police investigating the incident are still hunting the three men involved.

After a similar incident in 2008 it took the flock around three months to return to their normal behaviour.