Some conservation organisations in Africa are operating a shoot-to-kill policy against poachers, to protect endangered species, a study says.
An academic from the University of Manchester told the BBC that private security firms and mercenaries were being used to train game rangers.
Prof Rosaleen Duffy has researched the issue for 15 years for a book to be published this month.
She said these military-style campaigns were occurring across the continent.
War for wildlife
Ms Duffy says the development of nature tourism has meant international pressure to save high-profile species is intense.
Some conservation groups regard the protection of the gorilla, rhino and other endangered species as more important than human life, she says.
In countries, including Zimbabwe, the Democratic Republic of Congo and Malawi, private security firms have been brought in to provide military-style protection for these iconic animals.
Subsistence hunting is banned in many parks and often only tourists with hunting licences on safari are permitted to kill animals, she says.
This can mean local people are regarded as threats to the wildlife that have to be halted at almost any cost.
"Because private military operations and also park rangers are given authority to shoot on sight, the suspected poachers, then they can shoot first and ask questions later," she told the BBC.
"I think what happens then is that local people get justifiably very angry about people being shot because they're suspected of poaching whereas in fact what they might be doing is simply taking a short cut through a national park or they might be collecting grass for thatch."
Ms Duffy concedes that some poachers are heavily armed professionals - often former members of security forces - who are only too willing to open fire themselves.
But escalating this war for wildlife is, in Ms Duffy's view, not the way forward.
She argues that conservationists should work with local people, so that they value the animals that wander near their homes.