ZOO keepers in South Devon are starting the jumbo task of counting each and every animal in their collections for a new year stock-take.

The head-count is completed every January as part of compliance with legislation, which requires zoos to keep precise records of every animal birth, death, arrival and departure.

The chore can throw up interesting challenges — from finding a suitable method for counting thousands of tiny insects to distinguishing one penguin from another.

Staff at Paignton Zoo have almost 2,000 heads to count, including almost 450 mammals of 66 different species, more than 1,000 birds of almost 150 species, 268 reptiles, 71 amphibians and 61 blind cave fish.

A zoo spokesman said: "Some keepers have their work cut out at this time of year. It's easier to count our two elephants than it is to count our hundreds of Brazilian giant cockroaches."

Orangutans, saltwater, Nile and Cuban crocodiles and two female giraffes are just some of the additions to the inventory at Paignton Zoo this year.

Meanwhile, staff at Living Coasts have scores of new species to count in the new Mangroves exhibit, ranging from poisonous rays, horseshoe crabs and puffer fish to mudskippers, fiddler crabs and four-eyed fish.

At the last count, Torquay's coastal zoo had almost 400 individuals of 22 species.

Marine biologist Jodie Peers said: "The crabs are hard to count as they don't stand still very long."

Zoo curator of birds Jo Gregson said: "We get as many keepers out in the grounds as possible and count at the same time. We do it on several occasions and it takes about four weeks."

The data is submitted to the British and Irish Association of Zoos and Aquariums, the national professional body for zoo management and animal welfare.

The association's director Dr Miranda Stevenson said: "It's important zoos ensure their figures are correct so they can best manage conservation.

"Some of the species in captivity, such as Socorro doves, are now extinct in the wild. Therefore when zoos submit data to these central databases, it means that we can run detailed and scientifically-based breeding programmes to safeguard these valuable and threatened species."

The stock-take is being conducted at the one acre Shaldon Wildlife Trust, which specialises in monkeys and primates, and is one of the smallest zoos in the UK.