This week will be the last chance to see fat bats before they go into hibernation.

In preparation for the five winter months of sleep, bats eat up to a third of their body weight each night.

October 5 will see the final bat walk of the year directed by the council's biodiversity team through Cheam Park.

The walk will begin at Whitehall Museum in Cheam at 6.45 pm.

In August, the winged and often maligned critters start to swarm - a phenomenon which can not be explained.

The bats swarm around entrances to caves and roosts.

Some believe it is part of social bonding or mating.

Coun Colin Hall, Environment spokesman for Sutton Council said:”As the nights draw in, bats start behave in new ways as they prepare for their months of hibernation. An autumn bat walk is a great opportunity to see these interesting activities, and October will be your last chance to see bats in Sutton until they wake up in the spring.”

Booking for the event is essential and there is a charge of £3.50.

To book tickets call 02086431236.