Baby elephants have a greater chance of survival if their mothers are relaxed and well rested, according to University of Sheffield experts.
Elephants live in a seasonal environment but, unlike a lot of species, do not have a single breeding season.
Now pioneering research shows calves born during particular months are 44 per cent more likely to survive.
The findings could prove vital to endangered Asian elephants and help to increase population numbers.
The Department of Animal and Plant Sciences accessed records of the life and deaths of more than 2,000 working elephants from Burma.
The unique archive was recorded from 1948 to 2000, spanning five generations of elephants – a remarkable feat considering the animals can live up to 80 years.
Elephants in the data base are semi-captive animals working in the timber industry, pushing and dragging logs.
The extensive study showed 41 per cent of elephants are born in December to March and conceived in the months February to May.
During these months elephants have a rest from work every year as work stops in the hottest and driest months.
The research also showed elephants are less likely to be born May to August which corresponds to being conceived in the heavy working monsoon months of July to October.
Lead author Hannah Mumby said: “It seems that although elephants can reproduce at any time of year, they are reproducing more when conditions are best so maximising the chances of their calves surviving.
“If the number of conceptions in the rest period were possible across the year, the annual calving rate could be increased by 25 per cent, meaning 18 more baby elephants a year.”