Most of the 22 elephants that have died in the Pandamasue Forest – between the vast Hwange National Park and Victoria Falls – were young or weak, National Parks and Wildlife Management Authority spokesman Tinashe Farawo said on Wednesday (local time).
With food scarce, younger elephants that can’t reach higher tree branches “end up eating everything and some of the vegetation that they eat might be poisonous”, Mr Farawo said.
He said the problem could persist through the dry season.
Zimbabwe has faced successive climate-induced droughts, leaving animals with less water and vegetation.
Apart from possible bacterial infection, some of the animals could be dying due to the stress of walking long distances for food and water.
Mr Farawo said overpopulation had become “the biggest threat” to the survival of wildlife in the southern African country’s parks. The “animals are becoming a threat to themselves”, he said.
Investigations will also try to establish if there is a link between the deaths and those reported in neighbouring Botswana.
Scientists are also investigating the deaths in July of more than 275 elephants in Botswana’s Okavango Delta area.
Poaching, poisoning and anthrax have been ruled out for those deaths, with a senior wildlife official pointing to a naturally occurring toxin as a probable cause.
Botswana has the world’s largest elephant population, estimated at 156,000 and Zimbabwe the second largest, estimated at 85,000.
Last year about 200 elephants in Zimbabwe died of starvation as a result of the country’s drought.