It's been centuries since they last met, but the little spotted kiwi bird and the ancient tuatara reptile are showing evolutionary rivalries die hard.
New research footage of the two native New Zealand species tussling over a nesting spot has suggested they may be ancient foes in the wild.
The two species had not encountered each other for about 300 years on New Zealand soil, until they were reunited in 2005 as part of conservation translocations.
Night footage of the kiwi and tuatara getting into a scrape at Zealandia Sanctuary, in Wellington, has caused researchers at the University of Otago and Victoria University to consider the possibility they may have competed for habitats throughout history.
"New Zealand is a pretty unique place when it comes to biodiversity," lead researcher Helen Taylor said of the study just published in the New Zealand Journal of Ecology.
"However, it's unique in some negative ways too. Thanks to human activity, many of the country's native species have experienced big reductions in both numbers and the range they occupy.
"This means that some species in New Zealand that used to encounter one another regularly have been kept apart for hundreds of years by human actions."
Between 2011 and 2013, the New Zealand researchers monitored little spotted kiwi nests at Zealandia using motion-triggered camera traps.
The cameras were there to establish the presence of little spotted kiwi chicks and monitor the outcome of nesting attempts.
"However, at one nest, we got more than we bargained for," Taylor said.
"Over 20 minutes in the wee hours of a February morning, we recorded footage of a male little spotted kiwi and tuatara engaging in aggressive behaviour.
"This culminated in some dramatic lunging by the tuatara and some ferocious foot-stamping by the little spotted kiwi. All while the little spotted kiwi chick hid in the nest."
But does this surprising footage indicate ecological management needs to be applied to kiwi and tuatara in the future?
"Most likely not at this stage without evidence that tuatara actually pose a threat to kiwi eggs or chicks," Taylor said.
"The recording does, however, offer a window into the lives and interactions of these two iconic species."